xxk speeding up unit guide - physicslocker 3/unit k.pdfpupils do a quiz where the answers to...

XX Unit guide

Sheet 1 of 1© Harcourt Education Ltd 2004 Catalyst 3This worksheet may have been altered from the original on the CD-ROM.

K Speeding up

Where this unit fits in Prior learningThis unit builds on:work in unit 7K Forces and their effects. It relates to some of the ideas in unit 9J Gravity and space.

The concepts in this unit are: unbalanced forces cause changes in speed, using graphs to represent movement, the effect of water andair resistances.

This unit leads onto:further work on forces in unit 9L Pressure and moments.

This unit relates to:work on resistant materials in the design and technology scheme of work.

To make good progress, pupils startingthis unit need to:• be able to use the concept of speed

and describe changes of speed• know that forces cause a change in

movement.

Framework yearly teaching objectives – Forces• Use friction in liquids and gases to explore how the resistance to an object moving through liquids and gases changes with the object’s speed and

shape.• Explain how streamlining reduces an object’s resistance to air and water.

Expectations from the QCA Scheme of WorkAt the end of this unit …

… most pupils will … … some pupils will not have madeso much progress and will …

… some pupils will have progressedfurther and will …

in terms of scientific enquiry NC Programme of Study Sc1 2f, g, h, i, j, k, l, m

• measure the speed of moving objects in the laboratory using adatalogger

• describe patterns in data, and use these to make predictions andcheck them

• recognise that different degrees of precision are required formeasuring speed in different contexts

• interpret distance–time graphs of falling objects and relatethese to the forces acting on objects

• present a report, based on secondary sources, on an aspect ofthe development of faster vehicles.

• measure the speed of some movingobjects and relate these to speeddata from secondary sources

• identify factors affecting the fallof parachutes

• describe an invention which hashelped people to travel faster.

• describe non-linear relationshipsbetween speed and distance travelled

• justify appropriate levels of precision inmeasuring speed

• interpret speed–time graphs of fallingobjects

• explain how a technologicaldevelopment contributed to fastertravel.

in terms of physical processes NC Programme of Study Sc3 1b; Sc4 2a, c, d

• manipulate and apply the relationship between speed, distanceand time

• relate forces acting on an object to its movement• describe how streamlining reduces resistance to air and water

and how this resistance increases with the speed of the object,and relate this to the particle model

• apply ideas of unbalanced and balanced forces to falling objects.

• compare speeds• describe how forces change

movement• give examples of streamlined

objects• identify the forces acting on an

object.

• use the definition of speed in calculationsand conversions from different units

• relate change in movement of an objectto its mass and the forces acting upon it

• explain increased air resistance with thespeed of an object, using the particletheory.

MisconceptionsThat objects slow down because they are not being pushed (rather than because of an opposing force).When forces on an object are balanced, its speed is zero (rather than steady).

Health and safety (see activity notes to inform risk assessment)Risk assessments are required for any hazardous activity. In this unit pupils use forcemeters with fast-moving, massive objects.

K1Racing

K2Measuringspeed

K3Changing speed

K4Faster!

K5Slow down

Booster 5Focus on forces –Forces all around

Suggested lesson allocation (see individual lesson planning guides)Direct route

Extra lessons (not in Pupil book)

K5 Investigate: Howdid faster vehiclesdevelop?

Review and assessprogress (distributedappropriately)

J-L-Unit Guides.qxd 22-Jun-04 4:20 PM Page 6


K1Lesson planning

guideRacing

Suggested alternative starter activities (5–10 minutes)

Introduce the unit

Unit map for Speeding up.

Learning objectivesi Calculate speed.ii Represent speed on a distance–time graph.iii Understand acceleration. (red only)iv Represent changes in speed on a speed–time graph. (red only)

Scientific enquiryv Analyse simple data about movement using graphs. (Framework YTO Sc1 9f)

Learning outcomes

Share learningobjectives

• Represent speed on adistance–time graph.

• Describe how speed canchange.

• Explain how to calculatespeed. (Sc1)

Problem solving

Match speeds to variousmoving objects.

Brainstorming

Pupils brainstorm how wecan measure the speed ofvarious objects.

Capture interest

Show video clips of racingcar, train and aircraftadvances over the last 100 years.Catalyst InteractivePresentations 3

Suggested alternative plenary activities (5–10 minutes)

Review learning

Pupils complete a tableshowing distance, time andspeed for the motion ofvarious objects.

Sharing responses

Pupils discuss theirresponses to Activity K1a.

Group feedback

Compare results toActivity K1b.

Word game

Pupils answer clues tofill in a grid and find amystery word.

Looking ahead

Show a video clip of things that record fastspeeds. Ask what the devices are actuallymeasuring and how the speed is computed.Catalyst Interactive Presentations 3

Suggested alternative main activitiesActivity

Textbook K1

Activity K1a Paper

Activity K1b Practical

Activity K1cCatalyst InteractivePresentations 3

Learningobjectivessee above

i, ii, iii, ivand v

i, ii and v

i, ii and v

i, ii and v

Description

Teacher-led explanation and questioning OR pupils work individually,in pairs or in small groups through the in-text questions and then onto the end-of-spread questions if time allows.

Calculating speed Pupils use distance–time graphs to work out thespeed of an object.

Steady speed Measure steady speed using light gates and air track.

Show animation of car travelling at a constant speed. Indicatedistance travelled at 1 second intervals and build up a distance–timegraph.

Approx. timing

20 min

25 min

10 min

10 min

Target group

C H E S

R/G G R S

✔ ✔

✔

✔ ✔ ✔ ✔

Key wordsspeed, unit, distance–time graph, gradient, red only: speed–time graph,acceleration, deceleration

Out-of-lesson learningHomework K1Textbook K1 end-of-spread questionsResearch speed records; the teacher can restrict it to one type, such asathletes or cars

Most pupils will ...

• manipulate and apply the relationshipbetween speed, distance and time

• know that the gradient of a distance–timegraph shows the speed.

Some pupils, making less progress, will ...

• compare speeds of moving objects.

Some pupils, making more progress, will ...

• also use the definition of speed incalculations and conversions from differentunits

• also use speed–time graphs to showmovement.



K2Lesson planning

guideMeasuring speed


Recap last lesson

Show a distance–time graphas an OHT.Pupils answer somequestions about the graph.

Learning objectivesi Pupils measure fast speeds, including the speed of sound.

Scientific enquiryii Choose measuring devices with suitable precision. (Framework YTO Sc1 9b)iii Use repeated readings to increase accuracy. (Framework YTO Sc1 9d)

Learning outcomes

Share learningobjectives

• Describe how to measurefast speeds.

• Choose the most suitablemeasuring devices for atask. (Sc1)

• Use repeated readings toincrease reliability. (Sc1)

Problem solving

Demo to measure the speedof sound using twomicrophones and amillisecond timer.

Brainstorming

Drop a £10 note or a rulebetween a volunteer pupil’sfingers and ask him or herto catch it. Use this tointroduce the idea ofreaction time and its effecton the timing of short timeintervals.

Capture interest

Show a video clip of aselection of instruments thatmeasure time. Ask pupils tocompare them and suggestwhich they would choose forcertain uses and why.Catalyst InteractivePresentations 3


Review learning

Working in groups, pupils writedown five important facts aboutspeed. Each group reports backto class. List made on boardwhich can be copied down.

Sharing responses

Pupils discuss theirresponses to Activity K2b.

Group feedback

Group feedback onActivity K2a.

Word game

True/false/unsure quiz withpupils holding up cards.

Looking ahead

Show a video clip of themepark rides with obviouschanges in speed.Catalyst InteractivePresentations 3


Textbook K2

Activity K2a Practical

Activity K2b ICT



i, ii and iii

i, ii and iii

i and ii

iii

Description


Measuring the speed of sound Measure the speed of sound outdoorsusing clapping method and/or method described in textbook. Discussprecision, reliability and accuracy.

How have the speeds of sound and light been measured? Pupilsuse books and/or the Internet to research the ways in which thespeeds of sound and light have been measured. Could includehomework, preparing a presentation, etc.

Show animations of a car being timed over a measured distance withrepeat readings being taken.

Approx. timing

20 min

30 min

30 min

15 min

Target group

C H E S

R/G G R S

✔

✔

✔

Key wordsprecision, reliable, red only: accuracy

Out-of-lesson learningHomework K2Textbook K2 end-of-spread questionsComplete Activity K2b (if started in class)


• recognise that different degrees of precisionare required for measuring speed in differentcontexts

• learn to distinguish between precision andaccuracy

• understand that repeating measurements andtaking an average can lead to greateraccuracy.


• realise that very fast speeds are difficult tomeasure.


• also justify appropriate levels of precision inmeasuring speed

• relate the design of the experiment to theprecision required.



K3Lesson planning

guideChanging speed


Recap last lesson

Four volunteers come tothe front of the class. Askeach in turn to speak for1 minute to impress the classwith their knowledge. Therest of the class take notesand vote for the best talk.

Learning objectivesi Objects travel at a steady speed unless a force acts on them.ii Unbalanced forces cause changes in speed.iii Calculating the resultant force.

Scientific enquiryiv Using light gates and dataloggers to measure speed.v Interpreting data using graphs. (Framework YTO Sc1 9d)

Learning outcomes

Share learning objectives

• Explain why objects travel ata steady speed.

• Explain why unbalanced forcescause changes in speed.

• Calculate the resultant force.• Interpret data using graphs.

(Sc1)

Problem solving

Five examples on OHTshowing the forces actingon a car. Pupils decide onits initial direction oftravel.

Brainstorming

Pupils do a quiz where theanswers to questionsabout speed are numbers.

Capture interest

Pupils watch an animationof a rocket travelling intospace with several changesin speed.Catalyst InteractivePresentations 3


Review learning

Show an OHT of part of arailway timetable. Pupilsdraw a distance–time graphto represent the journey and answer some questionsabout it.

Sharing responses

Teacher-led discussion ofActivity K3a.

Group feedback

Groups report back onActivity K3b.

Word game

Pupils solve anagrams ofwords connected withspeed and then use themin a sentence to showtheir meaning.

Looking ahead

Drop two balls of different sizesfrom the same height (say 1 m)simultaneously. Then drop thesmaller ball and a sheet of paperface down in the same way. Askpupils for their observations.


Textbook K3


Activity K3b ICT

Activity K3c Paper

Activity K3d Catalyst InteractivePresentations 3


i, ii, iii and v

i, ii, iv and v

i, ii, iv and v

i and ii

i, ii and iii

Description


Travelling at speed Demonstration of forces on trolley.

Speeding trolleys Using light gates to look at speeding up andslowing down when moving up and down on ramps.

Speed–time graphs Pupils answer questions involving speed–timegraphs.

Animation showing objects moving with forces acting on themsuperimposed.

Approx. timing

20 min

15 min

35 min

15 min

10 min

Target group

C H E S

R/G G R S

✔ ✔

✔ ✔ ✔

✔

✔

Key wordsresultant force, steady speed

Out-of-lesson learningHomework K3Textbook K3 end-of-spread questionsActivity K3cSketch a distance–time graph of your journey to school (and estimateyour speed at each stage)


• measure the speed of moving objects in thelaboratory using a datalogger

• describe patterns in data and use these to makepredictions and check them

• interpret distance–time graphs• relate forces acting on an object to its movement.


• measure the speed of some movingobjects

• describe how forces change movement• identify the forces acting on an object.


• also describe non-linear relationships betweenspeed and distance travelled

• also relate change in movement of an objectto its mass and the forces acting upon it.



K4Lesson planning

guideFaster!


Recap last lesson

Pupils complete sentencesrelating to the materialintroduced in the lastlesson.

Learning objectivesi Relate the speed of a vehicle to the forces acting on it.ii Understand that the air resistance of an object depends on its shape (streamlining).iii Understand that air resistance changes with speed.

Scientific enquiryiv Relate streamlining and air resistance to the particle model.

Learning outcomes


• Describe how the speed of avehicle is related to theforces acting on it.

• Explain why the airresistance of an objectdepends on its shape(streamlining) and its speed.

• Use the particle model toexplain streamlining and airresistance. (Sc1)

Problem solving

Drop a small ball and afeather in a long tube.Remove most of the airfrom the tube. Repeat toshow the effect of airresistance.

Brainstorming

Play the ‘Tip of my tongue’game.

Capture interest

Show video clips ofexamples of streamlining.Catalyst InteractivePresentations 3


Review learning

Pupils complete some quickmultiple-choice questions toreinforce the points made inthe lesson.

Sharing responses

Teacher-led discussion ofActivity K4b.

Group feedback

Group feedback on Activity K4a.

Word game

Play ‘Give me a letter’ game.

Looking ahead

Run a toy car or trolleyalong different surfaces.Measure how far it goesbefore stopping.


Textbook K4

Activity K4a ICT

Activity K4b ICT

Activity K4c Catalyst InteractivePresentations 3


i, ii, iii and iv

i and ii

i

ii, iii and iv

Description


Streamlined shapes Drop different shapes made from modellingmaterial into wallpaper paste in a tall measuring cylinder andmeasure speed to find which one is most streamlined.

How do forces affect speed? Use an air track to investigate how thepulling force applied to a vehicle affects its speed.

Animation showing air bumping into a car as its speed increases.

Approx. timing

20 min

25 min

25 min

5 min

Target group

C H E S

R/G G R S

✔

✔ ✔

✔

Key wordsthrust, air resistance, drag

Out-of-lesson learningHomework K4Textbook K4 end-of-spread questionsExamine data on fuel consumption in cars, or collect some pictures ofcars and list the features of their design that help them go fast


• describe how streamlining reduces resistance toair and water

• describe how this resistance increases with thespeed of the object

• relate this to the particle model.


• describe an invention which has helpedpeople to travel faster

• give examples of streamlined objects• identify the forces acting on an object.


• explain how a technological developmentcontributed to faster travel

• explain why air resistance increases with thespeed of an object, using the particle theory.



K5Lesson planning

guideSlow down

Learning objectivesi Discuss examples of using friction (including air resistance) to slow objects down.ii Apply knowledge and understanding of forces to interpret the falling of a parachutist.

Scientific enquiryiii Use graphs to describe and analyse movement of falling objects.

Learning outcomes


Textbook K5


Activity K5b Paper



i and ii

i and ii

ii and iii

i and ii

Description


Making parachutes Pupils select materials and make and test aparachute in a class competition.

Falling! Pupils describe the motion of a parachutist’s fall from adistance–time graph. They explain the shape of each section of thegraph, relating it to the forces acting on the parachutist. Speed–timegraph for Extension.

Show objects moving on the level and/or vertically, representing thesize and direction of the forces acting by arrows of appropriatelength, and link to the motion of the object.

Approx. timing

20 min

30 min

15 min

10 min

Target group

C H E S

R/G G R S

✔

✔ ✔ ✔

✔

Key wordsNone

Out-of-lesson learningHomework K5Textbook K5 end-of-spread questionsActivity K5bFind out more about one of the examples in the Capture interest Starteractivity, or go over the topics learned in this unit


• interpret distance–time graphs of fallingobjects and relate these to the forces actingon objects

• apply ideas of unbalanced and balanced forcesto falling objects.


• describe how forces change movement• identify the forces acting on an object.


• interpret speed–time graphs of falling objects.


Recap last lesson

Pupils all stand up and sitdown when they haveanswered a question.


• Describe how friction is usedto slow objects down.

• Interpret the motion of afalling parachutist from agraph. (Sc1)

• Use graphs to describe andanalyse the movement offalling objects. (Sc1)

Brainstorming

Show pupils a photo orvideo clip of a fallingskydiver (adopting splayed,horizontal position). Askthem to suggest why theparachutist falls in thatposition.Catalyst InteractivePresentations 3

Problem solving

Watch the motion of twosimilar pendulums, onelightly damped and theother heavily damped. Askpupils to account for thedifference in their motion.

Capture interest

Show video clips of objectsslowing down withoutbrakes.Catalyst InteractivePresentations 3


Review learning

Pupils fill in the gaps in apassage summarising theunit.

Sharing responses


Group feedback

Group feedback onActivity K5a.

Word game

Play a loop game to checkprogress.

Looking back

Pupils revise andconsolidate knowledge fromthe unit.



K5Lesson planning

guideInvestigate: How did fastervehicles develop?

Learning objectivesi Use the Internet to learn about the development of faster vehicles.ii Present information about the development of faster vehicles.

Scientific enquiryiii Use data from secondary sources to support the aspect chosen for a presentation on the development of faster vehicles.iv Evaluate the strength of evidence collected.

Learning outcomes

InvestigationActivity

Activity K5d ICT


i, ii, iii andiv

Description

How did faster vehicles develop? Pupils use secondary sources toinvestigate how inventions have helped people travel faster, e.g.human-powered vehicles such as bikes.They prepare a presentation to describe one such invention. They canprepare group PowerPoint® presentations or leaflets. This couldextend into a homework activity with presentations in the nextlesson.A list of websites is provided to get pupils started (or teachers mayprefer to have this as a prompt for pupils who need some initialhelp).

Approx. timing

40 min

Target group

C H E S

✔


• use appropriate strategies to find informationfrom a range of secondary sources

• present a report, based on secondary sources,on an aspect of the development of fastervehicles.


• use appropriate strategies to find informationfrom secondary sources

• present information on one aspect of thedevelopment of faster vehicles.


• use appropriate strategies to find and selectkey information from a range of secondarysources

• prepare and present a detailed report, basedon secondary sources, on an aspect of thedevelopment of faster vehicles.


Setting the context

Show a video clip of a penny-farthing and a modern racing bike.Pupils consider the reasons for thedifferences in design.Catalyst Interactive Presentations 3

Introduce the apparatus

Recap web search techniques.Discuss how the information is tobe presented at the end of thesearch.

Brainstorming (1)

Show a video clip of various aspectsand types of vehicle that could beconsidered, e.g. man-poweredflight, ships, trains, aircraft.Catalyst Interactive Presentations 3

Brainstorming (2)

Teacher-led discussion of suitableapproaches to the investigation.


Review learning

Pupils look at each other’spresentations.

Group feedback

Pupils discuss how easy it was tofind suitable and relevantinformation.

Analysing

Pupils discuss their findings. Theycompare the development ofvarious types of travel.

Evaluating

Pupils discuss how useful andreliable their information sources are.


K Unit mapSpeeding up


Copy the unit map and use these words to help you complete it.You may add words of your own too.

acceleration Raccuracy Rbrakesdeceleration Rdistancedistance–time graphdraggradientparachuteparticlesprecision

reliableresultant force slowing downspeeding upspeed–time graph Rsteady speedstreamlinedthrusttimeunit

Speeding up

What is speed? Air resistance and friction

Streamlining

Changing speed

Measuring speed

Unitmaps.qxd 18-Jun-04 11:36 AM Page 11


K1 StartersRacing

Introduce the unit� Either draw the outline of the unit map on the board, then ask pupils

to give you words to add, saying where to add them. Suggest some wordsyourself when necessary to keep pupils on the right track.

� Or give out the unit map and ask pupils to work in groups, decidinghow to add the listed words to the diagram. Then go through it on theboard as each group gives suggestions.

Share learning objectives� Write the learning objectives on the board and show why it is important

that we know about these ideas.

� Tell pupils about some of the information you can get from adistance–time graph.

� Tell pupils how important it is to be able to calculate speed.

Problem solving� Pupils match speeds to various moving objects shown on an OHT.

Brainstorming� Pupils suggest how we can measure the speed of various objects.

� Choose a range of speeds so that different techniques are required. Someof the objects mentioned in the Problem solving starter could be used asexamples.

� For slow-moving objects such as a snail, a stopclock could be used tomeasure the time to travel a few centimetres.

� For faster-moving objects, pupils should be led to realise that thedistance, and hence the time, measured must be increased to obtain ameaningful result using a stopclock.

� This may lead to a discussion about better ways of measuring time.

Capture interest� Pupils watch video clips of racing cars over the last 100 years as well as

train and aircraft advances.

� Ask pupils to identify what changes have taken place.

� Ask pupils to suggest why these changes in cars, trains and aircraft haveoccurred.

➔ Unit map

➔ Pupil sheet

Answers (all in m/s)1 10; 2 0.0005; 3 330; 4 0.000002; 5 30000; 6 2.5; 7 30; 8 60

➔ Catalyst InteractivePresentations 3


Introduce the unit

Unit map for Speeding up.


• Represent speed on adistance–time graph.

• Describe how speed canchange.

• Explain how to calculatespeed. (Sc1)

Problem solving

Match speeds to variousmoving objects.

Brainstorming

Pupils brainstorm how wecan measure the speed ofvarious objects.

Capture interest

Show video clips of racingcar, train and aircraftadvances over the last 100years.Catalyst InteractivePresentations 3

K-Starters.qxd 18-Jun-04 9:53 AM Page 1

K1 StartersRacing

Problem solving

Match each of these speeds (in m/s) to the correctmoving object in the list.

0.000002 0.0005 2.5 10

30 60 330 30000

1 100m runner

2 snail

3 sound

4 glacier

5 Earth in orbit around the Sun

6 person walking

7 car travelling on a motorway

8 express train




K2 StartersMeasuring speed

Recap last lesson� Pupils answer questions about a distance–time graph shown

on an OHT.

Share learning objectives� Write the learning objectives on the board and show why it is

important that we know about these ideas.

� Tell pupils why it is important to be able to measure fastspeeds. They will probably mention speeding motorists butmay need to be led to examples of echo-location (radar, sonar).

� Tell pupils that it is important to select the right measuringdevice for each task and repeat readings for good reliability.

Problem solving� Clap hands near one microphone to produce a short, sharp

sound to show how to measure the speed of sound.

� The millisecond timer will show how long the sound took totravel the measured distance between the two microphones.

� Repeat readings three or four times and calculate an average.

Brainstorming� Drop a £10 note between a volunteer pupil’s fingers and ask

them to catch it to show reaction time and its effect on thetiming of short time intervals.

� As an alternative, or in addition, drop a 50 or 100cm rulebetween a volunteer pupil’s fingers and note the scale readingat which he or she catches it.

� Repeat with two or three other pupils, or allow all pupils to tryit, working in pairs.

� Reaction times can be quoted for interest (if ruler falls 20cm,reaction time is about 0.20s, for 40cm 0.28s, for 50cm 0.32s,and for 100cm 0.45s). The event is anticipated so times willbe less than for an unexpected event (typically 0.6–0.7s).

Capture interest� Pupils watch a video clip of instruments that measure time.

� Ask pupils to compare them and suggest which they wouldchoose for certain uses and why: timing a long train journey,estimating the time for midday lunch, timing a 100m race,giving a patient medication at four-hourly intervals, a wristwatch for someone who never needs to know the exact time.

➔ Pupil sheet

Answers1 0–2s; 2 2–5s; 3 5–7s;4 7–10s; 5 56m; 6 5.6m/s

Equipment

Equipment£10 note; 50 or 100cm rule

➔ Catalyst Interactive Presentations 3


Recap last lesson

Show a distance–timegraph on an OHT.Pupils answer somequestions about thegraph.


• Describe how to measure fastspeeds.

• Choose the most suitablemeasuring devices for a task.(Sc1)

• Use repeated readings toincrease reliability. (Sc1)

Problem solving

Demonstration tomeasure the speed ofsound using twomicrophones and amillisecond timer.

Brainstorming

Drop a £10 note or a rulebetween a volunteer pupil’sfingers and ask him or her tocatch it. Use this to introducethe idea of reaction time andits effect on the timing ofshort time intervals.

Capture interest

Show a video clip of a selectionof instruments that measuretime. Ask pupils to compare themand suggest which they wouldchoose for certain uses and why.Catalyst InteractivePresentations 3

sound-operatedswitches

'stop'microphone

electronicstopclock

d metres

'start'microphone

clap here


K2 StartersMeasuring speed

Recap last lesson

A car passes alamp post. Everysecond for 10 seconds, itsdistance from the lamp post is measured. Adistance–timegraph for the caris plotted. Usethe graph toanswer thesequestions.

1 Betweenwhich timeswas thespeed of the car increasing?

2 Between which times was the car travelling at asteady speed?

3 Between which times was the speed of the cardecreasing?

4 Between which times was the car stopped?

5 How far does the car travel in the first 7 seconds?

6 What is the car’s average speed over the whole10 second period?


Dis

tanc

e in

met

res

0 1 2 3 4 5 6 7 8 9 100

10

20

30

40

50

60

Time in seconds



K3 StartersChanging speed

Recap last lesson� Ask four volunteers to come to the front of the class.

� Ask each in turn to speak for 1 minute to impress theclass with their knowledge.

� The rest of the class take notes and vote for the best talk.

Share learning objectives� Ask pupils to write a list of FAQs they would put on a

website telling people about the effect of forces on speed.

� Collect suggestions as a whole-class activity, steeringpupils towards those related to the objectives.

� Conclude by highlighting the questions you want themto be able to answer at the end of the lesson.

Problem solving� Pupils look at five examples on OHT showing the forces

acting on a car.

� Pupils decide on its initial direction of travel.

Brainstorming� Pupils do a quiz where the answers to questions about

speed are numbers.

� Read out questions from the teacher sheet, selectingquestions appropriate to your pupils.

� Ask a volunteer pupil to answer each question andexplain how they worked it out.

Capture interest� Pupils watch an animation of a rocket launch.

� This is followed by a spacecraft in deep space travelling ina straight line at constant speed.

� The spacecraft then changes direction by firing a rocketor approaching a planet.

� The emphasis should be on the changes in speed thatoccur. You may wish to re-run the video clip in slowmotion to focus on each speed change.

➔ Pupil sheet

Answers1 remains at rest; 2 to the right;3 to the left; 4 to the right; 5 to the left

➔ Teacher sheet

Equipmentcalculator



Recap last lesson

Four volunteers come to the frontof the class. Ask each in turn tospeak for 1 minute to impressthe class with their knowledge.The rest of the class take notesand vote for the best talk.


• Explain why objects travel at asteady speed.

• Explain why unbalanced forcescause changes in speed.

• Calculate the resultant force.• Interpret data using graphs. (Sc1)

Problem solving

Five examples on OHTshowing the forcesacting on a car.Pupils decide on itsinitial direction oftravel.

Brainstorming

Pupils do a quizwhere the answersto questions aboutspeed are numbers.

Capture interest

Pupils watch an animation ofa rocket travelling into spacewith several changes inspeed.Catalyst InteractivePresentations 3



Problem solving

• The diagrams show the forces acting on a car.

• The length of the line representing each force isproportional to the size of the force.

• For each diagram decide whether the car will start tomove to the left, move to the right or remain at rest.

1 2

3 4

5




BrainstormingTeacher sheetRead out the questions below, selecting those appropriate to your pupils.

The questions are labelled H (Help), C (Core) and E (Extension).

1H Tom runs 100m in 10s.What is his average speed in metres per second? [10]

2H How many seconds will a car travelling at a steady speed of 20m/s take to go 240m? [12]

3H Jo measures the length of a line as 5cm; Pat says it is 48mm.Which value is more precise? [48]

4H In a 400m race four runners clock times of 46s, 53s, 57s and 45s.What was the winning time in seconds? [45]

5H Three snails move 21mm, 25mm and 24mm in 5 minutes.How many millimetres does the snail that moves fastest travel? [25]

6C The number 22 bus goes 5km in 30 minutes; the number 38 bus takes 40 minutes to go 6km.Which number bus is quicker? [22]

7C Ravi stands 32m from a brick wall. He claps his hands and hears the echo after 0.2s.What value does he get for the speed of sound in metres per second? [320]

8C A train travels 180km at an average speed of 90km/h.How many hours does the journey take? [2]

9C Harry measures the speed of sound three times and gets values of 331, 327 and 341m/s.What is his mean value in metres per second? [333]

10C Sam cycles at 5m/s for 1 minute.How many metres does she travel? [300]

11C A car travels 126km in 3 hours.What is its average speed in kilometres per hour? [42]

12C A 1500m runner takes 3 minutes 20 seconds to complete a race.What is his average speed in metres per second? [7.5]

13E How many kilometres does a ship travel in 5 hours at an average speed of 25km/h? [125]

14E How many minutes will it take Amy to walk 1.5km to school if she walks at 2km/h? [45]

15E Which speed is faster – 30m/s or 100km/h? [30]

16E Sound travels at 330m/s. Dan shouts at a wall and hears the echo after 3s.How far is he from the wall (in metres)? [495]




K4 StartersFaster!

Recap last lesson� Pupils complete sentences relating to the key points

introduced in the last lesson.

Share learning objectives� Write the learning objectives on the board and show

why it is important that we know about these ideas.

� Tell pupils that if they are aware of the forces acting onan object they will be able to tell how it is moving.

� Tell pupils that it is important to design objects so thatthey are streamlined, thus reducing the effect of airresistance and increasing their maximum speed.

� Tell pupils how air resistance can be linked to theparticle model.

Problem solving� Drop a small ball and a feather in a long tube. The

feather will fall much more slowly than the ball.

� Remove most of the air from the tube.

� Drop the ball and feather again to show the effect of airresistance. They fall at nearly the same rate.

� Safety! Place safety screens between the apparatus andthe pupils. The teacher should wear eye and faceprotection and protective gloves in case the tubeimplodes. Use only a glass tube designed to be evacuated and check for cracks before each use. Thisdemonstration should be practised beforehand.

Brainstorming� Write on the board the first part of the sentence as

shown on the right.

� Ask pupils to write down how they would finish thesentence.

� Ask for suggestions and write them on the board.Discuss any problem areas.

Capture interest� Pupils watch video clips of examples of streamlining.

� Ask pupils what is common to all the examples shown.

➔ Pupil sheet

Answers1 are balanced.2 the difference between the forward and

backward forces.3 backwards is greater than the force

forwards.4 a straight line.5 increasing.

Equipmentglass tube about 1m long fitted with arubber bung at one end and a rubber bungwith a central hole for a narrow glass tubeat the other; a small ball; a feather; avacuum pump with a means of connectingto the narrow glass tube

The maximum speed of a car depends on …



Recap last lesson

Pupils completesentences relating to thematerial introduced inthe last lesson.


• Describe how the speed of a vehicle isrelated to the forces acting on it.

• Explain why the air resistance of an objectdepends on its shape (streamlining) andits speed.

• Use the particle model to explainstreamlining and air resistance. (Sc1)

Problem solving

Drop a small ball and afeather in a long tube.Remove most of the airfrom the tube.Repeat to show theeffect of air resistance.

Brainstorming

Play the ‘Tip of myTongue’ game.

Capture interest

Show video clips ofexamples of streamlining.Catalyst InteractivePresentations 3


K4 StartersFaster!

Recap last lesson

Complete these sentences.

1 If a train is going at a steady speed, the forces acting on it

.

2 The resultant force on an object is

.

3 If a car is slowing down, the force

.

4 The distance–time graph for a car going at a steady speed is

.

5 If the speed of a car is increasing, the gradient of its distance–time graph is

.

Sheet 1 of 1

Sheet 1 of 1

© Harcourt Education Ltd 2004 Catalyst 3This worksheet may have been altered from the original on the CD-ROM.

StartersK4 Faster!


Recap last lesson

Complete these sentences.

1 If a train is going at a steady speed, the forces acting on it

.

2 The resultant force on an object is

.

3 If a car is slowing down, the force

.

4 The distance–time graph for a car going at a steady speed is

.

5 If the speed of a car is increasing, the gradient of its distance–time graph is

.



K5 StartersSlow down

Recap last lesson� Ask pupils to stand. Ask each in turn to explain the meaning of

one of the words on the right.� Pupils who give a correct explanation can sit down.� Differentiate the words so that all pupils sit down after the second

or third attempt. This can also be achieved by using some wordsmore than once.

Share learning objectives� Write the learning objectives on the board and show why it is

important that we know about these ideas.� Tell pupils how friction is used to slow down objects such as cars

and bikes.� Tell pupils how it can be useful to interpret the motion of a falling

parachutist from a graph.� Tell pupils how graphs can be used to describe and analyse the

movement of falling objects.

Brainstorming� Show pupils a photo or video clip of a falling parachutist

(adopting splayed, horizontal position).� Ask them to suggest why the parachutist falls in that position.� Lead pupils towards the idea of maximising air resistance so that

the parachutist falls more slowly. You may need to show thephoto or video clip again.

Problem solving� Set two similar pendulums, one lightly damped and the other

heavily damped, swinging with the same initial amplitudes.� Ask pupils to compare the motion of the two pendulums. If

necessary, lead them to compare the way in which the amplitudeof each pendulum changes, so that they agree that the amplitudeof the heavily damped pendulum decreases more rapidly.

� Ask pupils to suggest a reason for the difference in their motion,leading them to ideas about air friction. The more able pupils maytalk about collisions between the pendulums and the air particlescausing friction (air resistance).

Capture interest� Show video clips of objects slowing down without brakes.� Ask pupils to suggest why the objects slow down.

Wordsspeed; thrust; air resistance; drag;friction; streamlined; newton;balanced forces; resultant force;gradient; steady speed; light gate


Equipmenttwo strings of equal length(50–100cm) attached to twosimilar bobs or weights; twopieces of card (15cm × 10cmapprox.), one attached to eachbob using plasticine or stickytape; two clamp standsThe pendulums are set swingingso that the card on one is in theplane of oscillation (lightlydamped) and that on the other isat right angles to the plane ofoscillation (heavily damped)



Recap last lesson

Pupils all stand upand sit down whenthey have answered aquestion.


• Describe how friction is used toslow objects down.

• Interpret the motion of a fallingparachutist as a graph. (Sc1)

• Use graphs to describe andanalyse the movement of fallingobjects. (Sc1)

Brainstorming

Show pupils a photo or video clipof a falling parachutist (adoptingsplayed, horizontal position). Askthem to suggest why theparachutist falls in that position. Catalyst Interactive Presentations 3

Problem solving

Watch the motion of twosimilar pendulums, onelightly damped and theother heavily damped.Ask pupils to account forthe difference in theirmotion.

Capture interest

Show video clips ofobjects slowing downwithout brakes. Catalyst InteractivePresentations 3



K5 StartersInvestigate: How did fastervehicles develop?

Setting the context� Show a video clip of a penny-farthing and a modern racing bike.

� Pupils consider the reasons for the differences in design.

Introduce the apparatus� Recap web search techniques if necessary, using Skill sheet 4:

Web searches.

� Encourage pupils to consider the forces acting on a vehicle sothat they can explain why it goes faster than a previous model.

� Discuss how the information is to be presented at the end of theinvestigation. This could be a group presentation with eachmember researching a different type of vehicle. Possible ideascould be a leaflet, a poster (or set of posters), a file ofinformation, or a PowerPoint presentation.

Brainstorming (1)� Show a video clip of various aspects and types of vehicle that

could be considered, e.g. man-powered flight, ships, trains(‘Rocket’, steam train, TGV, magnetic levitation, bullet train),aircraft (Wright brothers, propeller-driven and jet engines,Concorde).

� Lead a discussion on the merits of different types of vehicle andhow their design has developed over time.

Brainstorming (2)� Lead a discussion on suitable approaches to the investigation.

� Encourage diversity, both in the type of vehicle selected and inthe aspect investigated. For example, some pupils may choose toadopt a historical approach while others may elect to focus onrecent technological developments.




Setting the context

Show a video clip of a penny-farthingand a modern racing bike. Pupilsconsider the reasons for the differencesin design.Catalyst Interactive Presentations 3

Introduce the apparatus

Recap web search techniques.Discuss how the information isto be presented at the end ofthe search.

Brainstorming (1)

Show a video clip of various aspectsand types of vehicle that could beconsidered, e.g. man-powered flight,ships, trains, aircraft.Catalyst Interactive Presentations 3

Brainstorming (2)

Teacher-led discussion of suitableapproaches to the investigation.


K1aTeacher

activity notesCalculating speed

Running the activityPupils complete a worksheet to calculate speed.

Core: Pupils analyse and draw distance–time graphs.

Help: Pupils work individually or in pairs to answer the questions. Theyreinforce their learning of the concept of speed and practise using the equation for speed.

Other relevant materialSkill sheet 39: Interpreting graphs (2)

ICT opportunitiesPupils doing the Core activity can plot their distance–time graph using aspreadsheet.

AnswersCore:

1 20 km/h

2 7.5 km/h

3 One that rises quickly.

4 One that rises slowly.

5 Between the third and fifth hours, because he travelled no distance at all.

6 6.43 km/h

7 C

8 A

9 B

10 D

11 D

Help:

1 cat 10m/s, dog 5 m/s, kangaroo 80 m/s

2 Mark is quicker at 10 m/s, while James runs at a speed of 8 m/s.

3 A 80 km/h, B 100 km/h, C 40 km/h; train B is fastest.

4 640 km/h


Type Purpose DifferentiationPaper Pupils use distance–time graphs to work out the speed of an object at each stage of its

journey. The Help activity concentrates on the concept of speed and practises using theequation for speed.

Core, Help

0

200

400

600

800

1000 B

AD

C

10 20 30 40Time in seconds

Dis

tanc

e in

met

res

K-Teachers.qxd 18-Jun-04 1:35 PM Page 1

K1aActivity

CoreCalculating speed

You can work out the speed of an object at each stage of its journey by plotting a graph of distance travelled against time. In this activity, you are going to use distance–time graphs to calculate speed.

The graph shows the journey made by a cyclist. It is possible to calculatethe speed of the cyclist by finding howfar he travelled over a period of timeand using the equation for speed. For example, over the first 2 hours(stage 1) the cyclist travelled 10 km.This is a speed of 10 km/2 h = 5 km/h.

Use this graph to answer Questions 1 – 6 .

1 Calculate the speed between the second and third hours (stage 2).2 Calculate the speed between the fifth and seventh hours (stage 4).3 What sort of line on a distance–time graph indicates a fast speed?4 What sort of line on a distance–time graph indicates a slow speed?5 At what time do you think the cyclist stopped to have lunch, and why?6 What is the average speed for the whole journey?

Draw a distance–time graph on graph paper of the four cars A–D in this table.


Car Time in seconds

0 10 20 30 40

Distance in metres

A 0 200 400 600 800

B 0 400 800 900 1000

C 0 100 300 300 400

D 0 150 300 450 700

Use your graph to answer Questions 7 – 11 .

7 Which car stops for a time before starting again?8 Which car travels at a constant speed?9 Which car is slowing down?10 Which car is travelling the fastest at 40 seconds?11 All the cars start from the same point. If the shops are 4000 metres from the starting

point, and the cars travel at the same speed as they are travelling at the 40 secondspoint on your graph, which car will get to the shops first?

0

10

20

30

40

50

1 2 3 4 5 6 7Time in hours

stage 1 stage 2 stage 3 stage 4

Dis

tanc

e in

km

K-Activities.qxd 18-Jun-04 1:41 PM Page 1

K1aActivity

HelpCalculating speed

The speed of an object can be found by using:

distance travelledspeed =

time taken

Use the equation above to calculate the speed in thefollowing questions. Make sure you give units withyour answers.

1 Calculate the speed of the following animals:

� a cat that runs 20 metres in 2 seconds� a dog that walks 40 metres in 8 seconds� a kangaroo that jumps 800 metres in 10 seconds.

2 At the school sports day, Mark runs the 100 m in 10 s whileJames runs the 200 m in 25 s. Who was faster?

3 Calculate the speed of each train in the table below. Whichone is travelling the fastest?


Train A Train B Train C

Journey From Liverpool From Leeds From Ashfordto London to London to London

Distance 240 km 200 km 60 km

Time taken 3 hours 2 hours 1.5 hours

4 A plane travels from Vienna to London, a distance of 800 km,in 75 minutes. Calculate the speed of the plane.


K1bTeacher

activity notesSteady speed

Running the activityPupils work in small groups to find the speed of a vehicle moving on an airtrack. If only one air track is available, the activity can be run alongside ActivityK1a.

This could be carried out as a datalogging activity if you wish, but it seemssensible at this point to reinforce the method for calculating speed, leaving thedatalogger to be used later in the unit when considering changing speeds.

Expected outcomesPupils carry out the steady speed activity. They obtain a set of results andsuggest basic conclusions (the vehicle moves at a steady speed; the harder it ispushed the greater the steady speed).

PitfallsPupils should round their answers to a suitable number of decimal places.

The air track must be level.

The experiment must be set up so that the card passes through the light gatesand breaks the beam.

The light gates should not be too close to windows as the sunlight may affectthe results.

Safety notesPupils must take care when using apparatus connected to the mains electricitysupply. Don’t allow pupils access to the blower or to disconnect it from the airtrack.

ICT opportunitiesIt would be possible to set up a spreadsheet for the results and subsequentcalculations.

Answers1 To remove the friction force.

2 Speed is constant because no forces are acting on the vehicle in its directionof motion.

3 Speed is higher but remains constant for a greater pushing force as itimparts a greater initial velocity. Speed is lower but remains constant for asmaller pushing force as it imparts a smaller initial velocity.


Type Purpose DifferentiationPractical Pupils use an air track to measure the speed of a vehicle as it moves along the air

track. Light gates are used to measure the speed of the vehicle at two points.Core


K1bTechnician

activity notesSteady speed

EquipmentFor each group:� air track (with blower)� 2 light gates (with centisecond timers)� vehicle (to push along air track)� card (about 10 cm deep, positioned to

pass through light gates)� metre rule� 2 clamp stands (to support light gates)

For your informationRunning the activityPupils work in small groups to find thespeed of a vehicle moving on an air track. Ifonly one air track is available, the activitycan be run alongside Activity K1a.

This could be carried out as a datalogging activity if you wish, but it seemssensible at this point to reinforce the method for calculating speed, leaving thedatalogger to be used later in the unit when considering changing speeds.

Expected outcomesPupils carry out the steady speed activity. They obtain a set of results andsuggest basic conclusions (the vehicle moves at a steady speed; the harder it ispushed the greater the steady speed).

PitfallsPupils should round their answers to a suitable number of decimal places.

The air track must be level.

The experiment must be set up so that the card passes through the light gatesand breaks the beam.

The light gates should not be too close to windows as the sunlight may affectthe results.

Safety notesPupils must take care when using apparatus connected to the mains electricitysupply. Don’t allow pupils access to the blower or to disconnect it from the airtrack.

ICT opportunitiesIt would be possible to set up a spreadsheet for the results and subsequentcalculations.


Type Purpose DifferentiationPractical Pupils use an air track to measure the speed of a vehicle as it moves along the air track.

Light gates are used to measure the speed of the vehicle at two points.Core

card

vehicle

light gate Blight gate A

K-Technician.qxd 07-Jun-04 3:30 PM Page 1

K1bActivity

CoreSteady speed

You are going to use light gates and an air track to measurethe steady speed of a vehicle.

Obtaining evidence

1 Level the air track so that it is horizontal.2 Arrange the light gates, each connected

to a timer, as shown in the diagram.3 Draw up a table for your results, like the

one shown below.4 Measure the length of the card attached

to the vehicle (in cm). Write its value inthe table. This value will be used tocalculate the speed of the vehicle.

5 Switch on the blower. If levelledcorrectly, the vehicle will hover withoutmoving sideways. Adjust the air trackagain if necessary.

6 Place the vehicle at one end of the air track.

7 Check that thetimers are readingzero.

8 Push the vehicleand then release it so that it passesthrough both light gates.

9 Note the readings on each timer. Write them in the table.10 Calculate the speed of the vehicle as it passed through each

light gate using

distancespeed =

time

11 Repeat Steps 6 –10 for a smaller and a larger pushing forcethan that used in Step 8.

1 Why are you using an air track for this activity?2 What do you notice about the speed of the vehicle along the

air track? Explain your answer.3 What do you notice about the speed of the vehicle along the

air track when the initial pushing force is larger and smaller?Explain your answer.


card

vehicle

light gate Blight gate A

Wear eyeprotection.

Take carewhen using

apparatus connectedto the mainselectricity supply.

Length of card = cm

Time to pass Time to pass Speed at Speed at light gate A light gate B light gate A light gate B in seconds in seconds in cm/s in cm/s


K2aTeacher

activity notesMeasuring the speed of sound

Running the activityYou can use one or both methods, depending on the time available and accessto a suitable open space or wall.

Direct method

This method requires an open distance of at least 300m to get a reasonableresult. Pupils work in pairs to measure the time between seeing a clapper closedsharply and hearing the sound a measured distance away. Repeat readings aretaken to improve reliability. Readings are also taken in opposite directions totake account of any wind. Pupils work out a value for the speed of sound in air.

Echo method

This method requires a large plane wall with 60–100m free space in front of itto produce a good echo. Pupils work in pairs. One person claps his or her handsso that each clap is made just as he or she hears the echo return. The otherperson uses the stopwatch to measure the time for 20 echoes. Repeat readingsare taken to improve reliability. The time for the echo to return is found bydividing the average time by 20. Speed = (distance to wall and back)/(echo time)is used to work out a value for the speed of sound in air.

Expected outcomesPupils should obtain a reasonable value for the speed of sound in air by bothmethods, but the clapping method using echoes is likely to produce a betterresult. The speed of sound is temperature sensitive, varying between 330 and340m/s. Pupils should be able to obtain a value in the range 310–360m/s. Theexperiment is designed to be used as a vehicle to promote an understanding ofprecision, accuracy and reliability in experimental work.

Answers1 Repeating readings and taking a mean.

2 Using a stopwatch reading to hundredths of a second.

3 Making the time measurement as large as possible (by maximising thedistance and, with the echo method, timing a large number of claps). Pupilsmay also refer to taking readings in both directions with the direct method.

4 Pupils should be able to obtain a value in the range 310–360m/s.


Type Purpose DifferentiationPractical Pupils measure the speed of sound outdoors using the direct method described in the

textbook and/or the clapping method using echoes.Core


K2aTechnician

activity notesMeasuring the speed of sound

EquipmentDirect method� measuring wheel� large wooden clapper� stopwatch measuring to hundredths of a second

This method requires an open distance of at least 300 m to get a reasonableresult.

Echo method� measuring wheel� stopwatch measuring to hundredths of a second� large plane wall with 60–100 m free space in front of it

For your informationRunning the activityOne or both methods can be used, depending on the time available and accessto a suitable open space or wall.

Direct method

This method requires an open distance of at least 300m to get a reasonableresult. Pupils work in pairs to measure the time between seeing a clapper closedsharply and hearing the sound a measured distance away. Repeat readings aretaken to improve reliability. Readings are also taken in opposite directions totake account of any wind. Pupils work out a value for the speed of sound in air.

Echo method

This method requires a large plane wall with 60–100m free space in front of itto produce a good echo. Pupils work in pairs. One person claps his or her handsso that each clap is made just as he or she hears the echo return. The otherperson uses the stopwatch to measure the time for 20 echoes. Repeat readingsare taken to improve reliability. The time for the echo to return is found bydividing the average time by 20. Speed = (distance to wall and back)/(echo time)is used to work out a value for the speed of sound in air.

Expected outcomesPupils should obtain a reasonable value for the speed of sound in air by bothmethods, but the clapping method using echoes is likely to produce a betterresult. The speed of sound is temperature sensitive, varying between 330 and340m/s. Pupils should be able to obtain a value in the range 310–360m/s. Theexperiment is designed to be used as a vehicle to promote an understanding ofprecision, accuracy and reliability in experimental work.


Type Purpose DifferentiationPractical Pupils measure the speed of sound outdoors using the direct method described in the textbook

and/or the clapping method using echoes.Core


K2aActivity

CoreMeasuring the speed of sound

Working in pairs, you are going to measure the speed of sound outdoors. This sheet explains two ways of finding it; your teacher will tell you which method to use if there is not sufficient time to do both.

Equipment

Direct method

� measuring wheel � stopwatch measuring to � large wooden clapper hundredths of a second

This method requires an open distance of at least 300 m to get a reasonable result.

Echo method

� measuring wheel� stopwatch measuring to hundredths of a second� large plane wall with 60–100 m free space in front of it.

Obtaining evidence

Direct method

1 Select two points, as far apart as possible, in an open space such as a playing field.2 Use the measuring wheel to find the distance between these two points.

Record this distance in column 1 of the results table.3 Repeat this measurement, record the distance in column 2 and find the mean value.4 One person goes to the first point with the clapper and the other person

goes to the second point with the stopwatch.5 The person with the clapper closes it sharply, making a loud sound.6 The other person starts the stopwatch when he or she sees the clapper close, and stops

it when he or she hears the sound. Record the time in column 3 of the results table.7 Repeat this twice more. Record the times in columns 4 and 5 of the results table.8 Swap roles so that the sound travels in the opposite direction and take three

more readings. Record the times in columns 6, 7 and 8 of the results table.9 Calculate the mean time.10 Use speed = distance/time to work out a value for the mean speed of sound in air.

Echo method

1 Stand between 60 and 100 m in front of a large plane wall. The larger the distance the better your result should be.

2 Use the measuring wheel to find the distance from the wall. Record this distance in column 1 of the results table.

3 Repeat this measurement, record the distance in column 2 and find the mean value.4 One person claps his or her hands so that each clap is made just

as he or she hears an echo return.



K2aActivity

CoreMeasuring the speed of sound (continued)

5 The other person uses the stopwatch to measure the time for 20 echoes.6 Record this time in column 3 of the results table.7 Repeat five times, recording the results in columns 4–8 of the results table.8 Calculate the mean time for 20 echoes.9 Calculate the mean time for one echo (echo time) by dividing the

mean time found in Step 8 by 20.10 Use speed = (distance to wall and back)/(echo time) to work out

a value for the speed of sound in air.

Presenting the results

Direct method


Distance in metres Time in seconds

1 2 3 4 5 6 7 8

Mean distance= metres

Distance from wall Echo time for 20 clapsin metres in seconds

1 2 3 4 5 6 7 8

Mean distance Mean echo time for 20 claps = seconds

= metres

Mean echo time for 1 clap = seconds

Mean speed of sound = (mean distance)/(mean time) = m/s

Echo method

Mean speed of sound = (mean distance to wall and back)/(mean echo time) =m/s

Evaluating

1 What did you do to make your results more reliable?2 What did you do to make your results precise?3 What did you do to make your results more accurate?4 The speed of sound is accepted to be between 330 and 340 m/s (it travels faster

when the temperature is higher). Compare this with your result.

Mean time = seconds


K2bTeacher

activity notesHow have the speeds of soundand light been measured?

Running the activityPupils use the Internet, and other resources if they wish, to find out variousways in which the speeds of sound and light have been measured in the past ormore recently using new technology. The actual activity should last about30 minutes, but pupils could spend longer, including homework, and producea presentation or poster to summarise their findings. You may choose to directdifferent pupils, or groups of pupils, to focus on light or sound. Some pupilsmay concentrate on the historical methods, others on more modern methods.This could be an individual or a group activity.

Other relevant materialUseful websites are given below.

Information on the speed of soundInformation on the speed of light

Expected outcomesPupils learn about the various ways in which the speeds of sound and lighthave been measured, both historically and using modern technology. Byensuring that these different aspects are covered by different pupils, or groupsof pupils, the feedback session will be more interesting and informative.


Type Purpose DifferentiationICT Pupils use books and the Internet to find out various ways in which the speeds of sound

and light have been measured. This develops their information handling skills and theybecome familiar with the techniques developed to measure the speeds of sound and light

Core No pupil sheets


http://www.heinemann.co.uk/hotlinks/url.asp?urlid=9376


K3aTeacher

activity notesTravelling at speed

Running the activityThis activity involves a number of teacher demonstrations of a trolley moving in different ways:� trolley stationary – balanced� trolley moving at a steady speed – balanced� trolley speeding up – unbalanced, changes speed, faster� trolley slowing down – unbalanced, changes speed, slower� trolley going forwards around a left-hand corner – unbalanced, changes direction (Core only)

Core: The pupils summarise what is happening by using the activity sheet to help them draw forcediagrams. Further questions review different scenarios of balanced and unbalanced forces.

Help: Pupils observe the demonstrations and complete a results table. They also consider balanced andunbalanced forces relating to a sky diver jumping from an aeroplane.

Expected outcomesPupils review balanced and unbalanced forces.

AnswersCore:

1

Description Diagram of forces Balanced/unbalanced forces

Trolley standing still balanced

Trolley moving at a steady speed balanced

Trolley speeding up unbalanced

Trolley slowing down unbalanced

2 a Diagram of car with a big force arrow going forwards and a smaller force arrow going backwards.b Diagram of car with a small force arrow going forwards and a bigger force arrow going backwards.c It depends on the efficiency of the brake system, the weather conditions on the road, the grip of

the tyres and the speed of the driver’s reactions.

Help:

1 See table above.

2 a The sky diver is moving down at a steady speed and the forces are balanced.b As the parachute opens the force upwards is greater and the forces are unbalanced.c The sky diver has landed. The reaction force of the ground pushes up to balance the weight

of the sky diver pushing down.


Type Purpose DifferentiationPractical Demonstrations to show pupils how a trolley moves under the action of balanced and

unbalanced forces. Pupils watch the demonstrations and then answer questions on a sheet.Core, Help


K3aTechnician

activity notesTravelling at speed

Equipment� dynamics trolley

For your informationRunning the activityThis activity involves a number of teacher demonstrations of a trolley movingin different ways:

� trolley stationary – balanced� trolley moving at a steady speed – balanced� trolley speeding up – unbalanced, changes speed, faster� trolley slowing down – unbalanced, changes speed, slower� trolley going forwards around a left-hand corner – unbalanced, changes

direction (Core only)

Core: The pupils summarise what is happening by using the activity sheet tohelp them draw force diagrams. Further questions review different scenarios ofbalanced and unbalanced forces.

Help: Pupils observe the demonstrations and complete a results table. They alsoconsider balanced and unbalanced forces relating to a sky diver jumping froman aeroplane.

Expected outcomesPupils review balanced and unbalanced forces.


Type Purpose DifferentiationPractical Demonstrations to show pupils how a trolley moves under the action of balanced and

unbalanced forces. Pupils watch the demonstrations and then answer questions on asheet.

Core, Help


K3aActivity

CoreTravelling at speed

When a car moves at a steady speed, the forces on it arebalanced. The force from the engine is equal to that fromfriction such as air resistance. If a car moving at a steadyspeed then speeds up, the forces are no longer equal. Theyare unbalanced.

Your teacher is going to use a trolley to show the effects ofbalanced and unbalanced forces.

1 Make a table with the following columns:� description (to describe what happened to the trolleys)� diagrams (to show the force arrows acting on the trolley)� balanced or unbalanced forces.

2 The following demonstrations will be carried out by yourteacher:A trolley standing stillB trolley moving at a steady speedC trolley speeding upD trolley slowing downE trolley going around a left-hand corner.

1 Complete the table for each demonstration A, B, C and D.2 a A car is travelling along a road at a steady speed and wants

to overtake a lorry. It has to speed up to do this. Draw aforce diagram of the car when it speeds up.

b When the car gets to a red traffic light it has to stop. Draw aforce diagram of the car braking.

c Suggest what factors affect how quickly the car comes to astop after the driver sees the red light.


Keep feetand fingersaway from

speeding trolleys.Support rampscarefully so theycan’t fall.


K3aActivity

HelpTravelling at speed

When a car moves at a steady speed, the forces on it arebalanced. The force from the engine is equal to that fromfriction such as air resistance. If a car moving at a steadyspeed then speeds up, the forces are no longer equal. They are unbalanced.

Your teacher is going to use a trolley to show the effects ofbalanced and unbalanced forces.

1 Complete the table. Add force arrows to the diagrams.

2 These diagrams show a sky diver falling from an aeroplane.Describe what is happening in each diagram, and say whetherit is an example of balanced or unbalanced forces.


Description

Trolley standing still

Trolley moving ata steady speed

Trolley speeding up

Trolley slowing down

Diagram of forces Balanced or unbalancedforces?

a b c




K3bTeacher

activity notesSpeeding trolleys

Running the activityThis is an ICT activity that requires the use of datalogging equipment. If pupils are familiar withusing datalogging equipment, the activity can be run quickly, otherwise they may need ademonstration of the kit before they start. Instead of using datalogging equipment and light gates,the activity can be run using ticker tape.

Core: Pupils work in groups. They draw up their own results table, carry out the experiment andplot bar charts. They answer questions to analyse the results and evaluate the experiment.

Help: Pupils work in groups. They only run the trolley down the ramp at various heights and a tableis provided to record their results. They answer questions to analyse the results and evaluate theexperiment.

Extension: Pupils work in groups. They draw up their own results table, carry out the experimentand plot appropriate bar charts. Pupils also examine the effect of changing the mass of the trolley.They answer questions to analyse the results and evaluate the experiment.

Expected outcomesPupils carry out the speeding trolleys experiment. They obtain a set of results and suggest a basicconclusion (the higher the ramp, the faster the trolley) and evaluation.

PitfallsThe results from datalogging are very accurate, perhaps down to several decimal places. Pupils needto round to a suitable number of decimal places.

The experiment must be set up so that the card passes through the light gates and breaks the beam.Light gates should not be too close to windows as the sunlight may affect the results.

Safety notesUse a catch box at the bottom of the ramp to stop the trolleys. Make sure the ramps cannot fall offthe tables.

AnswersCore:

1 a increases b decreases 2 – (bar charts) 3 As the height of the slope increases, the speed ofthe trolley increases. When the trolley is pushed uphill, as the slope increases the speed of thetrolley decreases. 4 For example, repeat the experiment at least once and obtain a mean toimprove reliability.

Help:

1 increases 2 – (bar chart) 3 As the height of the slope increases, the speed of the trolleyincreases. 4 For example, repeat the experiment at least once and obtain a mean to improvereliability.

Extension:

1 a increases b decreases 2 – (bar charts) 3 a increases b no change 4 For example,accelerates down as there is a resultant force down the ramp; decelerates up as there is aresultant force down the ramp; as height of ramp increases, there is a bigger force down theramp due to gravity; as the mass of the trolley is increased, there is a bigger force down theramp due to gravity but also a bigger mass to move, so there is no change. 5 For example,repeat the experiment at least once and obtain a mean to improve reliability.


Type Purpose DifferentiationICT Pupils carry out a datalogging activity to measure the speed of a trolley travelling up

and down ramps of different slopes. Light gates are used to measure the speed of thetrolley at two points.

Core, Help, Extension


K3bTechnician

activity notesSpeeding trolleys

EquipmentFor each group:� computer� 2 light gates� spreadsheet software� trolley or toy car� card (10cm depth,

positioned to pass through light gates)

� metre rule� interface� datalogging software� printer (optional)� ramp, e.g. PVC guttering� Plasticine (to attach card

to car)� books (to support ramp)� clampstands (to hold

light gates)� weights to increase mass

of trolley (Extension only)

For your informationRunning the activityThis is an ICT activity that requires the use of datalogging equipment. If pupils are familiar with usingdatalogging equipment, the activity can be run quickly, otherwise they may need a demonstration of thekit before they start.

Instead of using datalogging equipment and light gates, the activity can be run using ticker tape.

Core: Pupils work in groups. They draw up their own results table, carry out the experiment and plot barcharts. They answer questions to analyse the results and evaluate the experiment.

Help: Pupils work in groups. They only run the trolley down the ramp at various heights and a table isprovided to record their results. They answer questions to analyse the results and evaluate the experiment.

Extension: Pupils work in groups. They draw up their own results table, carry out the experiment and plotappropriate bar charts. Pupils also examine the effect of changing the mass of the trolley. They answerquestions to analyse the results and evaluate the experiment.

Expected outcomesPupils carry out the speeding trolleys experiment. They obtain a set of results and suggest a basicconclusion (the higher the ramp, the faster the trolley) and evaluation.

PitfallsThe results from datalogging are very accurate, perhaps down to several decimal places. Pupils need toround to a suitable number of decimal places.

The experiment must be set up so that the card passes through the light gates and breaks the beam. Lightgates should not be too close to windows as the sunlight may affect the results.

Safety notesUse a catch box at the bottom of the ramp to stop the trolleys.

Make sure the ramps cannot fall off the tables.


Type Purpose DifferentiationICT Pupils carry out a datalogging activity to compare the speed of a trolley travelling up

and down ramps of different slopes. Light gates are used to measure the speed of thetrolley.

Core, Help, Extension


K3bActivity

CoreSpeeding trolleys

You are going to use light gates and datalogging software tomeasure the change in speed of a trolley as it travels up and down a ramp. You are going to change the height of the ramp and see how this affects the speed of the trolley.

Obtaining evidence

1 Set up the apparatus as shown in the diagram. You are going to measure the speed of the trolley at two places as it runs down the ramp.

2 Draw up a table to record your results.3 Start with the height of the ramp at 10 cm. Hold the trolley at the top of the ramp,

let it go and the computer will measure its speed as it passes each light gate.4 Repeat the experiment with ramp heights of 15 cm, 20 cm, 25 cm and 30 cm.5 Leave the ramp height at 30 cm. Push the trolley up the ramp and the

computer will measure its speed as it passes each light gate. You must push it hard enough so that it passes through both light gates.

6 Repeat Step 5 with ramp heights of 25 cm, 20 cm, 15 cm and 10 cm. Try to push the trolley with the same force each time.

Considering the evidence

1 What happens to the speed of the trolley as ita runs down the ramp?b runs up the ramp?

2 Draw bar charts of your results to show how the speed of the trolley at each lightgate changes with ramp height (or your teacher may give you printouts).

3 What happens to the speed of the trolley when the height of the ramp is increased?

Evaluating

4 Can you think of any improvements to this experiment?





K3bActivity

HelpSpeeding trolleys

You are going to use light gates and datalogging software to measure the change in speed of a trolley as it travels up and down a ramp. You are going to change the height of the ramp and see how this affects the speed of the trolley.

Obtaining evidence

1 Set up the apparatus as shown in thediagram. You are going to measurethe speed of the trolley at two placesas it runs down the ramp.

2 Start with the height of the ramp at10 cm. Hold the trolley at the top ofthe ramp, let it go and the computerwill measure its speed as it passes eachlight gate. Record the results.

3 Repeat the experiment with rampheights of 15 cm, 20 cm, 25 cm and30 cm. Record the results.



1 What happens to the speed of the trolley as it runs down the ramp?2 Draw a bar chart of your results to show how the speed of the trolley at each light

gate changes with ramp height (or your teacher may give you a printout).3 What happens to the speed of the trolley when the height of the ramp is increased?

Evaluating



Height of ramp Speed at first Speed at second in cm light gate in cm/s light gate in cm/s

10

15

20

25

30




K3bActivity

ExtensionSpeeding trolleys

You are going to use light gates and datalogging software tomeasure the change in speed of a trolley as it travels up and down a ramp. You are going to change

(i) the height of the ramp, and(ii) the mass of the trolley

to see how they affect the speed of the trolley.

Obtaining evidence

1 Start with the height of the ramp at 10 cm.Hold the trolley at the top of the ramp, let it go and the computer will measure its speed as it passes each light gate.

2 Draw up a table to record your results.3 Repeat the experiment with ramp heights of

15 cm, 20 cm, 25 cm and 30 cm.4 Leave the ramp height at 30 cm. Push the

trolley up the ramp and the computer will measure its speed as it passes each lightgate. You must push it hard enough so that it passes through both light gates.

5 Repeat Step 4 with ramp heights of 25 cm, 20 cm, 15 cm and 10 cm. Try to push the trolley with the same force each time.

6 Increase the mass of the trolley by adding weights to it. Repeat Steps 1–5. If you are short of time you need not do all the ramp heights again.


1 What happens to the speed of the trolley as ita runs down the ramp?b runs up the ramp?

2 Draw bar charts of your results to show how the speed of the trolley at each lightgate changes with ramp height and trolley mass (or your teacher may give youprintouts).

3 What happens to the speed of the trolley whena the height of the ramp is increased?b the mass of the trolley is increased?

4 Can you use your knowledge of physics to explain your results?

Evaluating





K-Activities.qxd 21-Jul-04 4:15 PM Page 10

K3cTeacher

activity notesSpeed–time graphs

Running the activityPupils answer two questions about speed–time graphs. In question 1 theyinterpret a given graph. In question 2 they draw a graph from given data andthen answer questions about it.


Expected outcomesPupils learn how to draw and use speed–time graphs.

PitfallsMake sure pupils do not confuse speed–time and distance–time graphs.

Answers1 a 0.2 m/s2

b 200 mc She travels at a steady speed of 8 m/s.

2 a,b

c 0.2 m/s2

d 0.6 m/s2

e 2880 m


Type Purpose DifferentiationPaper Pupils answer some questions based on speed–time graphs. Extension

Time in seconds

24

20

16

12

8

4

00 20 40 60 80 100 120 140 160 180 200

Spee

d in

m/s

ConstantSpeed

Slowing down(decelerating)

Speeding up(accelerating)


K3cActivity

ExtensionSpeed–time graphs

You are going to answer some questions based on speed–time graphs.

1 The speed–time graph for a cyclist over a 60 s period is shown in the figure.We can use the graph to find out how far the cyclist travels during the first 20 seconds:

distance = area under the graph between 0 s and 20 s

= 1—2 (20 s × 12 m/s) = 120 m

a Between 20 s and 40 s the cyclist slows down. Calculateher deceleration (rate of slowing down).

b How far does she travel between 20 s and 40 s?c What happens between 40 s and 60 s?

2 The data in the table was obtained during partof a car journey.a Draw a speed–time graph for the car journey.b Describe the motion of the car at each stage

of its journey. You may write on the graph.c Calculate the acceleration of the car in the

first 120 s.d Calculate the deceleration of the car in the

last 40 s.e How far did the car go?


Time in s Speed in m/s

0 0

20 4

40 8

60 12

80 16

100 20

120 24

140 24

160 24

180 12

200 0

Remember! Acceleration = gradient of a speed–time graph

Distance travelled = areaunder a speed–time graph

Spee

d in

m/s

0 10 20 30 40 50 600

2

4

6

8

10

12

Time in seconds


K4aTeacher

activity notesStreamlined shapes

Running the activityPupils use Plasticine to make several different shapes. They drop each shape, inturn, through a tall tube of wallpaper paste and use light gates connected to adatalogger and computer to measure the speed of each shape as it falls.

The light gates can be connected to centisecond timers if dataloggingequipment is not available. Pupils then make conclusions on speed based onthe length of each shape and the time taken to pass each light gate.

Expected outcomesPupils decide which shapes fall fastest (i.e. are most streamlined).

PitfallsMake sure the wallpaper paste is not too stiff.

Safety notesTake care when using equipment connected to the mains. Wallpaper pastecontains fungicides. Avoid skin contact and don’t let pupils retrieve their‘shapes’ from the paste.

Answers1 Answer depends on shapes made.

2 For example, smooth, nothing sticking out, curved, pointed ends butrounded middle, long and thin.

3 For example:

� dropping the objects through different liquids or different solutions ofwallpaper paste – the denser/more viscous (sticky) the liquid, the slowerthe speed; could reach a constant speed (terminal velocity) if forcesbecome balanced;

� using a greater variety of shapes – depends on shapes chosen; link with2 above;

� using a longer cylinder and more light gates – acceleration (increase inspeed) will decrease the further the object falls and speed may reach aconstant value if forces become balanced.


Type Purpose DifferentiationICT Pupils drop different Plasticine shapes through wallpaper paste and measure their speed

to find out which shape is the most streamlined.Core


K4aTechnician

activity notesStreamlined shapes

EquipmentFor each group:� Plasticine� tall measuring cylinder� wallpaper paste� 2 light gates� datalogger� computer

For your informationRunning the activityPupils use Plasticine to make several different shapes. They drop each shape, inturn, through a tall tube of wallpaper paste and use light gates connected to adatalogger and computer to measure the speed of each shape as it falls.

The light gates can be connected to centisecond timers if dataloggingequipment is not available. Pupils then make conclusions on speed based onthe length of each shape and the time taken to pass each light gate.

Expected outcomesPupils decide which shapes fall fastest (i.e. are most streamlined).

PitfallsMake sure the wallpaper paste is not too stiff.

Safety notesTake care when using equipment connected to the mains. Wallpaper pastecontains fungicides. Avoid skin contact and don’t let pupils retrieve their‘shapes’ from the paste.


Type Purpose DifferentiationICT Pupils drop different Plasticine shapes through wallpaper paste and measure their speed

to find out which shape is the most streamlined.Core

tall measuringcylinder

wallpaper paste

light gate B

light gate A

Plasticine shapetodatalogger

andcomputer


You are going to drop different Plasticine shapes through wallpaper paste and measure their speed to find out which shape is the most streamlined.

Equipment

� Plasticine � 2 light gates� tall measuring cylinder � datalogger� wallpaper paste � computer

Obtaining evidence

1 Use the Plasticine to make several different shapes.

2 Draw up a table similar to the one shownbelow to record your results.

3 Position the light gates at regular intervalsaround the measuring cylinder so thatthey can record the speed of each Plasticine shape as it falls.

4 Connect the light gates to the datalogger.5 Drop each shape, in turn, through the cylinder of wallpaper paste.6 Use light gates A and B to measure the speed of each shape as it falls

through the wallpaper paste.



Compare your results for each shape.

1 What sort of shapes fall fastest?2 What features make an object streamlined?

Evaluating

3 Suggest further experimental work you could do and predict what youwould expect to happen. This could involve• dropping the objects through different liquids• using a greater variety of shapes• using a longer cylinder and more light gates.

K4aActivity

CoreStreamlined shapes


tall measuringcylinder

wallpaper paste

light gate B

light gate A

Plasticine shapetodatalogger

andcomputer

Drawing of shape Speed at A Speed at B

Take carewhenusing

apparatus connectedto the mainselectricity supply.

Do not handle thewallpaper paste.


K4bTeacher

activity notesHow do forces affect speed?

Running the activityCore: Pupils use two light gates connected to a datalogger to record the speed of a vehicle moving on an airtrack for different pulling forces. The pulling force can be varied using a forcemeter or a pulley system withhanging weights. The use of a short glass rod instead of a pulley reduces friction on the string and givesgood results.

Extension: Pupils also change the mass of the vehicle by adding Plasticine or weights.

Expected outcomesCore and Extension: Pupils discover that the larger the pulling force the greater the speed of the vehicle ateach light gate. Some pupils may notice that there is a greater change in speed from one light gate to theother.

Extension: Pupils discover that as the mass of the vehicle is increased the speed at each light gate decreasesand there is a smaller change in speed from one light gate to the other.

PitfallsA forcemeter gives less good results as it is difficult to maintain a steady pulling force. Make sure thevehicle can move freely if using a pulley (or equivalent) method.

AnswersCore:

1 The speed at the second light gate will be greater than that at the first light gate.

2 Unbalanced force on vehicle makes it speed up.

3 As the pulling force is increased the speed at each light gate increases and there is a greater difference between the two speeds recorded.

4 Answer depends on experimental results.

5 For example, reduce friction of string on pulley, add a third light gate, extend range of pulling forces.

Extension:

1 The speed at the second light gate will be greater than that at the first light gate.

2 Unbalanced force on vehicle makes it speed up.

3 As the pulling force is increased the speed at each light gate increases and there is a greater difference between the two speeds recorded.


5 As the mass of the vehicle is increased the speed at each light gate decreases and there is a smallerdifference between the two speeds recorded.


7 For example, reduce friction of string on pulley, add a third light gate, extend range of masses.


Type Purpose DifferentiationICT Pupils use an air track to investigate how the pulling force applied to a vehicle affects

its speed.Core, Extension


K4bTechnician

activity notesHow do forces affect speed?

EquipmentFor each group:� linear air track with elastic band at one end� blower� vehicle with card of known length attached� two light gates connected to a datalogger and computer� forcemeter (or clamped pulley/short glass rod and hanging weights)

Extension only:� balance� Plasticine or weights (to change mass of vehicle)

For your informationRunning the activityCore: Pupils use two light gates connected to a datalogger to record the speed of a vehicle moving onan air track for different pulling forces. The pulling force can be varied using a forcemeter or a pulleysystem with hanging weights. The use of a short glass rod instead of a pulley reduces friction on thestring and gives good results.

Extension: Pupils also change the mass of the vehicle by adding Plasticine or weights.

Expected outcomesCore and Extension: Pupils discover that the larger the pulling force the greater the speed of thevehicle at each light gate. Some pupils may notice that there is a greater change in speed from onelight gate to the other.

Extension: Pupils discover that as the mass of the vehicle is increased the speed at each light gatedecreases and there is a smaller change in speed from one light gate to the other.

PitfallsA forcemeter gives less good results as it is difficult to maintain a steady pulling force. Make sure thevehicle can move freely if using a pulley (or equivalent) method.


Type Purpose DifferentiationICT Pupils use an air track to investigate how the pulling force applied to a vehicle

affects its speed.Core, Extension

towingforce

SAFETYUse a foam-lined

box for the mass to fall in

weighing scales(Extension only)

light gate to input Bof datalogger

vehiclelight gate to input A

of datalogger

linearair track


K4bActivity

CoreHow do forces affect speed?

You are going to use an air track to investigate how the pulling force applied to a vehicle affects its speed.

Obtaining evidence

1 Predict how you think the motion of the vehicle will change when you alter the pulling force applied to the vehicle. Do you think it will increase, decrease or stay the same?

2 Set up the apparatus as shown in the diagram so that a steady force can be applied to the vehicle.

3 Level the air track, measurethe length of the card onthe vehicle and switchon the blower.

4 Pull the vehicle alongthe air track, keepingthe reading on theforcemeter at aconstant value of (say)2 N, or with a 2 Nweight hanging fromthe clamped pulley,while the dataloggerrecords the speed of the vehicle at each light gate.

5 Repeat this procedure for four more constant pulling forces.6 Write down or print out your results using a table similar to the one shown below.



1 What do you notice about the speeds recorded at each light gate?2 Explain why the vehicle moves in this way.3 How does the motion of the vehicle change as the pulling force is increased?4 Does this agree with your prediction?

Evaluating

5 How could you improve this procedure?


towingforce





of datalogger

linearair track

Pulling force Speed at light Speed at light in N gate A in cm/s gate B in cm/s


K4bActivity

ExtensionHow do forces affect speed?

You are going to use an air track to investigate how(i) the pulling force applied to a vehicle, and(ii) the mass of the vehicle affect its speed.

Obtaining evidence

Changing the pulling force

1 Predict how you think the motion of the vehicle will change when you alter the pulling force applied to the vehicle.

2 Set up the apparatus as shown in the diagram so that a steady force can be applied to the vehicle.

3 Level the air track, measure the length of the card on the vehicle and switch on the blower.

4 Pull the vehicle along the air track, keeping the reading on theforcemeter at a constant value of (say) 2 N, or with a 2 N weighthanging from the clamped pulley, while the datalogger recordsthe speed of the vehicle at each light gate.

5 Repeat this procedure for four more constant pulling forces.6 Write down or print out your results using a suitable table.


towingforce



weighing scales



of datalogger

linearair track


K4bActivity

ExtensionHow do forces affect speed? (continued)

Changing the mass

7 Predict how you think the motion of the vehicle will changewhen you alter the mass of the vehicle.

8 Find the mass of the vehicle and card using a mass balance.9 Pull the vehicle along the air track, keeping the reading on

the forcemeter at a constant value of (say) 2 N, while thedatalogger records the speed of the vehicle at each lightgate as before.

10 Alter the mass of the vehicle by adding Plasticine or a weightto it. Find the new mass.

11 Repeat Step 9, keeping the pulling force at the same constantvalue.

12 Obtain results for five different vehicle masses.13 Write down or print out your results using a suitable table.


1 What do you notice about the speed of the vehicle as it passesthrough each light gate?

2 Explain why it moves in this way.3 How does the motion of the vehicle change as the pulling

force is increased?4 Does this agree with your prediction?5 How does the motion of the vehicle change as the mass of the

vehicle is increased?6 Does this agree with your prediction?

Evaluating

7 How could you improve the procedures used?



K5aTeacher

activity notesMaking parachutes

Running the activityPupils draw up a plan to construct a model parachute. They are given a fixedtime (say 30 minutes) to make their parachute, using a selection of materialsfrom the equipment provided. The winning parachute could be the one thattakes longest to fall.

A variety of suitable materials should be provided so that the pupils can maketheir own selection.

Pupils should be encouraged to modify their plans as construction proceeds,documenting any changes made. They should test their design within theallotted time so that final adjustments can be made prior to the launch.

Expected outcomesPupils successfully make parachutes using a variety of designs and materials.The final testing shows them the plan that is most successful.

Safety notesFinished parachutes must be launched from a safe point, such as a balcony,stairwell or exterior fire escape so that students do not need to climb onbenches, etc. Do not allow them to launch from open windows. Check toensure the ‘drop zone’ is clear.

ICT opportunitiesPupils could search the Internet for the development of parachute designand/or the style of parachute now used.

Answers1 Answer must fit in with the pupil’s design, but possible comments could

include:� large surface area to trap air, giving a large upward force� hemispherical shape to enclose the maximum volume with the

minimum surface area.

2 Low density/small mass to reduce the downward force; airtight, so air istrapped.

3 The parachute provides a large upward force; this reduces the net force onthe parachutist, slowing him or her down.

4 Sensible improvements; answer depends on the original design.


Type Purpose DifferentiationPractical Pupils work in groups to make a parachute which they then test Core


K5aTechnician

activity notesMaking parachutes

EquipmentFor each group:� a selection of suitable materials for the parachute, such as thin sheets of

polythene, tissue paper, silky or fine nylon fabric� thin string or thread� scissors� hole punch� Plasticine or small weights� paper and pencil

For your informationRunning the activityPupils draw up a plan to construct a model parachute. They are given a fixedtime (say 30 minutes) to make their parachute, using a selection of materialsfrom the equipment provided.

A variety of suitable materials should be provided so that the pupils can maketheir own selection.

Pupils should be encouraged to modify their plans as construction proceeds,documenting any changes made. They should test their design within theallotted time so that final adjustments can be made prior to the launch.

Expected outcomesPupils successfully make parachutes using a variety of designs and materials.The final testing shows them the plan that is most successful.

Safety notesFinished parachutes must be launched from a safe point, such as a balcony,stairwell or exterior fire escape so that students do not need to climb onbenches, etc. Do not allow them to launch from open windows. Check toensure the ‘drop zone’ is clear.

ICT opportunitiesPupils could search the Internet for the development of parachute designand/or the style of parachute now used.


Type Purpose DifferentiationPractical Pupils work in groups to make a parachute which they then test. Core


K5aActivity

CoreMaking parachutes

Working in groups, you are going to make a parachute using a selection of materials from the equipment provided. Each group will then test its parachute in front of the rest of the class.

Equipment

� materials for the parachute: � scissorspolythene, tissue paper, nylon fabric � hole punch

� thin string or thread � Plasticine or small weights

Planning

1 Design a parachute. It must fall gently to the ground when released so that your ‘parachutist’ is unharmed. You should consider

� its shape and size� the best material to use� how to construct it� how to represent the parachutist.

2 Draw up a detailed plan of your proposed parachute.

Constructing

3 Make your parachute using the materials provided. You may wish to test your parachute and then modify your design as you work, but make sure you amend your written plan too. Your teacher will tell you how long you have to complete your model.

Testing

4 Launch your parachute for testing when told to do so by your teacher.5 The winning parachute is the one that takes longest to fall.

Evaluating

1 Use your knowledge of physics to explain the shape and size you chose for your parachute.

2 What properties did you look for when selecting a suitablematerial for the parachute?

3 Explain why a parachute allows a person to fall to the ground safely.

4 What improvements would you make to your design if youwere going to construct another parachute?



K5bTeacher

activity notesFalling!


Running the activityCore: Pupils answer questions about a distance–time graph to link the forcesthat are acting to the motion of a parachutist at various stages of descent.

Help: Pupils answer questions about a distance–time graph to show the motionof a parachutist. They need to use the Core sheet for the graph.

Extension: Pupils answer questions about a speed–time graph to link the forcesthat are acting to the motion of a parachutist at various stages of descent.


Answers [Those in square brackets were provided on pupil sheets]

Core:

Help: 1 Motion: Same answers as column one above; 2 C; 3 E

Extension:

Type Purpose DifferentiationPaper Pupils answer questions about a distance–time graph (Core and Help) or a speed–time

graph (Extension) to show the motion of a parachutist.Core, Help, Extension

Section 1 Motion 2 , 3 Forcesof graph

OA [speed rapidly increasing] [weight (W) down]

AB speed increasing more and more slowly W down and a smaller force up of airresistance (R); arrow for W same throughout

BC steady speed W = R

CD very rapid slowing down as parachute opens R much larger than W

DE steady speed (much smaller than BC) R = W

EF slows down very rapidly as he hits very large upward reaction ground and stops force, with W as before

Section 1 Motion 2 , 3 Forces 4 Commentof graph

OA [speed rapidly [weight (W) down] [unbalanced downward force increasing] causes large acceleration]

AB speed increasing more W down and a smaller force as speed increases, air and more slowly up of air resistance (R); resistance increases so

arrow for W same throughout resultant force decreases

BC steady speed W = R forces are balanced

CD very rapid slowing R much larger than W parachute opens, causing down as parachute very large upward force and opens rapid deceleration

DE steady speed (much R = W forces balanced again but smaller than BC) at a much slower steady

speed due to large area of parachute canopy

EF slows down very very large upward reaction very large upward force fromrapidly as he hits force, with W as before ground causes large unbalancedground and stops upward force, so rapid deceleration


K5bActivity

CoreFalling!

You are going to look at a distance–time graph for a free-fall parachutist. You willdescribe the motion and explain the shape of each section of the graph by statingthe forces acting on the parachutist at that time.

For each labelled section of thegraph, copy and completethe table.

1 Describe the motion of theparachutist.

2 Add arrows to the diagrams of the parachutist to show the forces acting on him at that time. The length of eacharrow line should represent the size of the force. The firstone has been done for you.

3 Name any forces you add to the diagrams, including the weight of the parachutist.


Dis

tanc

e in

met

res

0 4 8 12 16 20 24 28 320

100

200

300

400

Time in seconds

A

B

CD

E F

Section of graph

OA

AB

BC

CD

DE

EF

Motion

speed rapidly increasing

Forces

weight


You are going to look at a distance–time graph for a free-fall parachutist.

1 For each labelled section of the graph, complete the table to describe themotion of the parachutist. The first one has been done for you.

2 At which point on the graph does his parachute open?3 At which point on the graph does he reach the ground?

K5bActivity

HelpFalling!


Section of graph

OA

AB

BC

CD

DE

EF

Motion


Forces

weight

weight

weight

weight

weight

weight


K5bActivity

ExtensionFalling!

You are going to look at a speed–time graph for a free-fall parachutist. You willdescribe the motion and explain the shape of each section of the graph.

For each labelled section of thegraph, copy and complete the table.

1 Describe the motion of theparachutist.

2 Add arrows to the diagrams ofthe parachutist to show theforces acting on him at thattime. The length of each arrowline should represent the size ofthe force.

3 Name any forces you add to thediagrams, including the weightof the parachutist.

4 In the last column explain why the force(s) have changed in the way you have shown. The first one has been done for you.


Spee

d in

m/s

0 4 8 12 16 20 24 28 320

10

20

30

40

5050

60

Time in seconds

A

B C

D E

F

Section of graph

OA

AB

BC

CD

DE

EF

Motion


Forces

weight

Comment

unbalanceddownward forcecauses largeacceleration


K5dTeacher

activity notesInvestigate: How did fastervehicles develop?


Running the activityPupils use the Internet to research the development of faster vehicles. They select a type of transport and an aspect of development to investigate. With your guidance they decide how to present their material in an interesting and informative way. This could be in the form of a poster, a leaflet or a PowerPoint presentation, for instance. You decide whether they are going to work independently or as part of a group. Finally, pupils are encouraged to evaluate the information they have collected.

Here are some websites to get them started. You may prefer to initiate your own search, provide a more limited number of sites or leave pupils to do their own searches.

Bikes

Bikefix – Bicycle design

Cars

Transport Japan – The history of transportThe Grid Club – Cars sectionLandspeed.comChannel 4 Science – Land speed record

Aircraft

Speed Record Club – Air speed recordAir Racing History

All vehicles

Speed Record Club – Speed records for all vehicles

PitfallsPupils should be discouraged from collecting too much information and warned against copying large amounts of text. Their presentations should be in their own words, perhaps with the inclusion of diagrams, graphs or data from secondary sources.

Type Purpose DifferentiationICT Pupils use the Internet to learn about the development of faster vehicles and prepare a

presentation on a chosen aspect.Core










K5dActivity

CoreInvestigate: How did fastervehicles develop?

You are going to use the Internet to research the development of faster vehicles and prepare a presentation on an aspect that you have chosen to investigate.

Planning

1 Select the type of vehicle you plan to research.2 Choose the aspect of the development of faster vehicles of this

type that you are going to research, e.g.� increasing the thrust of the engine� reducing friction� streamlining to reduce air resistance.

Your teacher may give you some websites to get you started, or you may prefer to initiate your own search.

Obtaining evidence

3 Collect together the information that is relevant to your chosen invention and aspect of development. Make sure you have some diagrams or photos. You may wish to include some data or graphs.

Evaluating the information

4 Evaluate the strength of the evidence you have collected. You should� consider the merits of the websites used� decide how reliable your information sources were� consider how easy it was to find relevant information about

your chosen aspect.

Presenting your research

5 Decide how to present your chosen material in an interesting and informative way. This could be in the form of a poster, a leaflet or a PowerPoint presentation, for instance. Your teacher will tell you whether you are going to work independently or as part of a group.

6 Edit your information into a presentation describing the development of your vehicle to increase its speed.




K1 PlenariesRacing

Review learning� Pupils complete a table showing distance, time and

speed for the motion of various objects.

Sharing responses� Pupils discuss their responses to Activity K1a.

� Make sure any wrong calculations or misconceptionsare clarified.

� If pupils carried out this activity at different levels(Core, Help), it would be useful to include responses onboth activities.

Group feedback� Pupils work in groups to discuss their responses to

Activity K1b.

� Make sure any misconceptions about steady speed areclarified.

Word game� Pupils solve five clues based on the lesson.

� Pupils write their answers in a grid to make a mysteryword.

Looking ahead� Pupils watch a video clip of things that record fast

speeds.

� Ask them what the devices are actually measuring (e.g.time to cover a measured distance).

� Ask them to suggest how the speed is computed.

➔ Pupil sheet

Answers1 120 km/h; 2 3 h; 3 1.5 km; 4 7.5 m/s;5 100s; 6 144 000 000 km

➔ Pupil sheet

Answers1 stopwatch or stopclock; 2 graph; 3 camera; 4 light gate; 5 Sadie mystery word: speed



Review learning

Pupils complete a tableshowing distance, timeand speed for the motionof various objects.

Sharing responses

Pupils discuss theirresponses to Activity K1a.

Group feedback

Compare results to ActivityK1b.

Word game

Pupils answer clues tofill in a grid and find amystery word.

Looking ahead

Show a video clip of things thatrecord fast speeds. Ask what thedevices are actually measuring andhow the speed is computed.Catalyst Interactive Presentations 3

K-Plenaries.qxd 18-Jun-04 12:02 PM Page 1

K1 PlenariesRacing

Sheet 1 of 1

Sheet 1 of 1


PlenariesK1 Racing


Review learning

Complete the following table.

Remember! Speed =distance

time

Distance Time Speed

1 Train journey from 240 km 2 hours km/hLondon to Cardiff

2 Royal Navy ship 180 km hours 60 km/h

3 Cheetah km 50 seconds 30 m/s

4 1500 m runner 1500 m 3 min 20 s m/s

5 Racing car 5 km seconds 50 m/s

6 Light from Sun to km 480 seconds 300 000 000 m/sEarth

Review learning

Complete the following table.

Remember! Speed =distance

time

Distance Time Speed

1 Train journey from 240 km 2 hours km/hLondon to Cardiff

2 Royal Navy ship 180 km hours 60 km/h

3 Cheetah km 50 seconds 30 m/s

4 1500 m runner 1500 m 3 min 20 s m/s

5 Racing car 5 km seconds 50 m/s

6 Light from Sun to km 480 seconds 300 000 000 m/sEarth


1

2

3

4

5

K1 PlenariesRacing

Word game

� Fill in the answers to the five clues in the grid below.� When you have finished, look at the shaded squares. What word

do they spell out that is connected with this lesson?

Clues

1 Used to time a 1500 m race.2 A good way to represent data connecting distances and times.3 Motorists must not drive too fast when one of these is around!4 Used to measure a much shorter time interval than a 1500 m

race.5 Tom walks 400 m in 180 s; Sadie walks 600 m in 240 s. Who

walks faster?




K2 PlenariesMeasuring speed

Review learning� Working in groups, pupils write down five important

facts about speed.

� Each group reports back to the class.

� A list is made on the board which can be copied down.

Sharing responses� Pupils discuss their responses to Activity K2b.

� Make sure all aspects of the research are covered.

� Make sure pupils have a clear understanding of the waysin which the speeds of sound and light have beenmeasured, both historically and by modern methods.

� By ensuring that these different aspects are covered bydifferent pupils, or groups of pupils, the feedbacksession will be more interesting and informative.


Activity K2a.

� The discussions should concentrate on the precision,accuracy and reliability of the methods used to decidewhich of the two methods gives the best results.

Word game� Make a set of cards for each pupil: ‘True’, ‘False’ and

‘Unsure’ (see the bottom half of the Teacher sheet). Youcould use a different colour card for each word.

� Read out the statements on the Teacher sheet. Pupilshold up the card for their answer simultaneously.

� Explain the answers. If many pupils get an answerwrong, repeat the statement later.

Looking ahead� Pupils watch a video clip of Alton Towers style rides

with obvious changes in speed.

� Ask pupils what they notice about the track when theriders are speeding up.

� Ask pupils what they notice about the track when theriders are slowing down.

➔ Teacher sheet



Review learning

Working in groups, pupilswrite down five importantfacts about speed. Eachgroup reports back to class.List made on board whichcan be copied down.

Sharing responses

Pupils discuss theirresponses to Activity K2b.

Group feedback

Group feedback on activityK2a.

Word game

‘True, False, Unsure’ quizwith pupils holding upcards.

Looking ahead

Show a video clip of themepark rides with obviouschanges in speed.Catalyst InteractivePresentations 3


K2 PlenariesMeasuring speed

Word gameTeacher sheetRead out the statements below and ask pupils to answer True or False (or Unsure)by holding up a card.

1 The speed of sound in air is about 330m/s. [True]

2 Speed is how fast something goes. [True]

3 Speed = distance × time. [False]

4 A more precise measuring instrument measures smaller amounts. [True]

5 Repeating an experiment and working out the mean makes your result more accurate. [False]

6 A stopwatch is a more precise instrument than a clock with only two hands. [True]

7 If a car travels 300km in 2½ hours, its average speed is 125km/h. [False]

8 To find speed, you need to measure distance and time. [True]

9 Sound travels much faster than light. [False]

10 Jo runs 100m in 14s but Sally takes 16s, so Sally runs faster than Jo. [False]

11 A speed of 25m/s is faster than a speed of 72km/h. [True]

12 If Darren repeats his readings his experiment will be more reliable. [True]

13 A light gate measures speed very precisely. [False]

14 3.5 hours is more precise than 212 minutes. [False]

15 When finding the speed of sound, you need to use a large distance so that thetime is maximised. [True]


Display the words below in large type for pupils to hold up for you to see.Make them into 2 × 4 = 8 cards to a sheet.

True TrueTrue TrueTrue TrueTrue True


False FalseFalse FalseFalse FalseFalse False


Unsure UnsureUnsure UnsureUnsure UnsureUnsure Unsure



K3 PlenariesChanging speed

Review learning� Pupils draw a distance–time graph for a train journey

from an OHT of part of a railway timetable.

� Pupils then answer some questions about their graph.

Sharing responses� Pupils discuss their responses to Activity K3a.

� Make sure any misconceptions are clarified.

� If pupils carried out this activity at different levels(Core, Help), it would be useful to include responses onboth activities.

� It may be useful to demonstrate some parts of theactivity again to reinforce ideas about forces and speed.


Activity K3b.

� The groups should be chosen so that all the pupils in agroup carried out the activity at the same level.

Word game� Pupils solve anagrams of words connected with speed.

� They then use each word in a sentence to show itsmeaning.

Looking ahead� Drop two balls of different sizes from the same height

(say 1 m) simultaneously.

� Then drop the smaller ball and a piece of paper with itslarge face horizontal in the same way.

� Ask pupils for their observations. For example, bothballs hit the ground together but the paper falls moreslowly than the ball.

� Ask pupils to suggest why this happens, leading thediscussion towards the idea of air resistance.

➔ Pupil sheet

Answers1 (graph); 2 100 km/h; 3 Swindon–Bristol;4 Bristol–Cardiff; 5 12.40

➔ Pupil sheet

Answers1 steady speed; 2 slowing down; 3 gettingfaster; 4 gradient; 5 resultant force

Equipmenttwo balls of different sizes, such as a tennisball and a golf ball (a ping-pong ball has toolow a mass to be unaffected by air resistanceif dropped 1 m); sheet of A4 paper; metrerule


Review learning

Show an OHT of part of arailway timetable. Pupilsdraw a distance–time graphto represent the journeyand answer some questionsabout it.

Sharing responses

Teacher-led discussion ofActivity K3a.

Group feedback

Groups report back onActivity K3b.

Word game

Pupils solve anagrams ofwords connected with speedand then use them in asentence to show theirmeaning.

Looking ahead

Drop two balls of differentsizes from the same height(say 1 m) simultaneously.Then drop the smaller balland a sheet of paper facedown in the same way. Askpupils for their observations.



Review learning

The table shows part of a railway timetable for a journeyfrom London to Cardiff.


Station Time Distance fromLondon in km

London 10.00 0(Paddington)

Reading Arrive 10.30 50Depart 10.35

Swindon Arrive 11.25 120Depart 11.30

Bristol Arrive 11.50 175Depart 12.00

Newport — 215

Cardiff Arrive 13.00 235

1 Draw a distance–time graph for the journey.2 What is the train’s mean speed, in kilometres per hour,

between London and Reading?3 Between which two stations does the train travel fastest?4 Between which two stations does the train have its

slowest mean speed?5 At what time did the train pass through Newport

station?



Word game

� Solve the following anagrams to find words connected with howthings move.

� Use each word or phrase in a sentence to make their meaningclear.

1 dysate deeps2 winglos wond3 gigtent strafe4 tendigar5 tunerlast cofer

Sheet 1 of 1

Sheet 1 of 1


PlenariesK3 Changing speed

Word game

� Solve the following anagrams to find words connected with howthings move.

� Use each word or phrase in a sentence to make their meaningclear.

1 dysate deeps2 winglos wond3 gigtent strafe4 tendigar5 tunerlast cofer




K4 PlenariesFaster!

Review learning� Pupils answer the multiple-choice quiz questions by

jotting down the letter for the answer.

� Go through each question and answer with the class,asking for a show of hands for each possible answer soyou can see how much pupils know.

Sharing responses� Lead a discussion on the pupils’ responses to Activity

K4b.


� If pupils carried out this activity at different levels(Core, Extension), it would be useful to includeresponses on both activities.


Activity K4a.

� One person from each group summarises the findings oftheir group.

Word game� Write the word ‘streamlined ‘ on the board.

� Ask pupils to list a word starting with each letter in‘streamlined’ that relates to the lesson.

� Taking each initial letter in turn, ask pupils for theirsuggested words and write them on the board. Go overany problems.

Looking ahead� Run a toy car or trolley along different surfaces. The car

should be released from rest down a ramp each time togive a fair test.

� Measure how far it goes before stopping.

� Ask pupils to comment on the results and steer themtowards links with friction.

➔ Pupil sheet

Answers1 c; 2 b; 3 a; 4 c; 5 b; 6 a

Equipmenttoy car or trolley; various surfaces (e.g.wood, carpet, cork, glass/Perspex); metrerule; raised ramp


Review learning

Pupils complete some quickmultiple-choice questions toreinforce the points made inthe lesson.

Sharing responses


Group feedback

Group feedback on ActivityK4a.

Word game

Play ‘Give me a letter’ game.

Looking ahead

Run a toy car or trolleyalong different surfaces.Measure how far it goesbefore stopping.


K4 PlenariesFaster!

Review learning

Choose the correct answer, a, b or c, for the following questions.

1 A car has a thrust of 300N and a friction force of 200N. Howwould you describe its motion?a slowing downb steady speedc speeding up

2 When does a car reach its maximum speed?a when it has been travelling for a long timeb when the thrust and friction are balancedc when the friction force is smallest

3 What do we call the friction force caused by a car pushing airout of the way as it goes along?a air resistanceb stressc tension

4 Which animal, a, b or c, is most streamlined?a crabb octopusc shark

5 Athletes often wear tight-fitting clothing. How does this helpthem to win races?a it increases the air resistance on themb it makes them more streamlinedc it keeps them warmer

6 What happens to the air resistance force on a car as its speedincreases?a increasesb decreasesc stays the same




K5 PlenariesSlow down

Review learning� Pupils fill in the gaps in a passage summarising the unit.

� Go through each answer with the class, asking for ashow of hands so you can see how much the pupilsknow.

Sharing responses� Lead a discussion on the pupils’ responses to Activity

K5b.


� If pupils carried out this activity at different levels(Core, Help, Extension), it would be useful to includeresponses on all activities.


Activity K5a.

� One person from each group summarises what madethe best parachute.

Word game� Give each pupil a card containing a question and an

answer. Ask one pupil to stand up and read out just thequestion on their card, then sit down. The pupil whohas an appropriate answer to this question stands up,reads out their answer, then asks the question on theircard and sits down, and so on.

� The game is complete when the pupil who started thegame stands up for a second time to read out the answeron their card. The loop is complete.

� If there are not enough question/answer cards for thewhole class, you may need to make extra copies. Somepupils will have the same question/answer card – thefirst one to stand up gets to read their answer and asktheir question.

Looking back� Pupils revise and consolidate knowledge from the unit.

� They can use the Unit map, the Pupil checklist or theTest Yourself questions.

➔ Pupil sheet

Answersthrust, balanced, steady, air resistance, drag,speed, shape, streamlined, decreases, faster,thrust, friction

➔ Teacher sheet

Answers

Answers are displaced down by one cardon each sheet, e.g.

Q. This formula is used to find averagespeed

A. Distance/time

➔ Unit map

➔ Pupil checklist

➔ Test Yourself


Review learning

Pupils fill in the gaps in apassage summarising the unit.

Sharing responses


Group feedback

Group feedback on ActivityK5a.

Word game

Play a Loop game tocheck progress.

Looking back

Pupils revise and consolidateknowledge from the unit.



Review learning

Complete the passage below using words from the list. Each word may be used once,more than once or not at all.

air resistance balanced decreases drag fasterfriction increases shape slow down slowerspeed steady streamlined thrust

The forward force on a car is called . If this force is

equal to the total friction force, the forces are said to be .

The car then travels at a speed. The car pushes air out of

the way as it travels; this is called or

and depends on the and of the car.

A shape the resistance to motion

so the car travels . The car reaches its maximum

speed when the is equal to the total force.




Word gameTeacher sheet


Q

The gradient of adistance–time graphtells you this.

Q

This formula is used tofind average speed

QThe echo of a soundfrom a wall 40m awayis heard after 0.25s.What value does thisgive for the speed ofsound?

Q

If a train travels 300kmin 2 hours, what is itsaverage speed?

Q

If an object travels ata steady speed, itsdistance–time graphlooks like this.

Q

When the forces on anobject are balanced itmoves like this.

Q

If an object is speedingup, its distance–timegraph looks like this.

Q

This is why a parachuteallows a person to fallmore slowly.

Q

If an object is slowingdown, its distance–timegraph looks like this.

Q

If an object has a bigger force forwardsthan backwards, it isdoing this.

A

a curve ofdecreasinggradient

A

speeding up

A

320m/s

A

speed

A

a curve ofincreasinggradient

A

a straight linethrough theorigin

A

distance/time

A

A 150km/h

A

It provides abigger upwardforce than theweight.

A

at a steadyspeed


K5 PlenariesSlow down (continued)


Q

Why are experimentalresults repeated?

Q

The pushing force of anengine is called this.

Q

When the thrust on avehicle is equal to thefriction force, thevehicle is doing this.

Q

This is the differencebetween the forwardand backward forces onan object.

Q

An object is designedto go faster if its shapeis like this.

Q

Drag is another namefor this.

Q

This can be used tomeasure a short timeinterval.

Q

Sound travels at330m/s. How longdoes it take to travel1320m?

Q

This causes airresistance.

Q

What happens to theair resistance on avehicle when it is going faster?

A

a movingobjectpushing airout of the way

A

increases

A

going at itsmaximumspeed

A

to increasereliability

A

light gate

A

streamlined

A

thrust

A

resultant force

A

4s

A

air resistance



K5 PlenariesInvestigate: How did fastervehicles develop?

Review learning� Pupils look at each other’s presentations.

� Pupils could vote for the best presentation or the mostinteresting fact discovered.

Group feedback� Pupils work in groups to discuss how easy it was to find

suitable and relevant information.

� One person from each group summarises the findings oftheir group.

Analysing� Pupils discuss their research findings.

� Pupils compare the development of various types oftravel to see whether there are any common features,e.g. to minimise air resistance, reduce weight, increasethrust, etc.

Evaluating� Pupils discuss how useful their information sources are.

� Pupils discuss how reliable their information sourcesare.


Review learning

Pupils look at each other’spresentations.

Group feedback

Pupils discuss how easy it was tofind suitable and relevantinformation.

Analysing

Pupils discuss their findings. Theycompare the development ofvarious types of travel.

Evaluating

Pupils discuss how useful andreliable their information sourcesare.


1 Write high or low to complete each sentence.

a If you travel a long distance in a short time then

your speed is .

b If you travel a short distance in a long time then

your speed is .

2 Draw lines to match the measurements to the unitsthey are measured in.

3 Michael timed how long it took his friend Lee towalk 50 m. Here are his results.

Use this to help you work out Lee’s speed.

K1 SpecialsRacing


distance

time

speed

seconds (s)

metres (m)

metres per second (m/s)

Distance Leewalked = 50 mTime Lee took

to walk it= 25 s

01

23

45

9

8

+

_

0

=.

%on

distance time speed

=÷............ m ............ s ............ m/s

K-Specials.qxd 18-Jun-04 9:56 AM Page 1

K1 SpecialsRacing (continued)

4 Susanne timed how long it took Sarah to jog 50 m.Here are her results.

Use this to help you work out Sarah’s speed.

5 Look at this distance–time graph for a car journey.

a Which part of the graph, A, B, C or D, shows the

car moving slowest?

b Which part of the graph, A, B, C or D, shows the

car moving fastest?


01

23

45

9

8

+

_

0

=.

%ondistance time speed

=÷............ m ............ s ........... m/s

time

distance

A

B

C

D

Distance Sarahran = 50 m

Time Sarahtook to run it= 10 s


K2 SpecialsMeasuring speed

1 Look at these measuring instruments.


C

10mm 20 30 40

B

1cm 2 3 4

A

1m

Circle the correct answer.

a Which is the most precise measuring instrument, A, B or C?

b Which is the least precise measuring instrument, A, B or C?

2 Look at thesemeasurements madeby some pupils.

a Whose measurementis the most precise?

and

b Whose measurement was the least precise?

and

c Sue and Maria measured the length of the class room twicemore. Their measurements were 9029 mm and 9021 mm.

Do this to work out the mean length of the class room.

i Add together all three measurements.

9025

ii Divide your answer by 3. 3

iii Your answer is the mean length of the class room

3 Underline the correct word to complete the sentences.

a A precise measuring instrument measures in smaller / larger amounts.

b A more / less reliable value comes from repeating a measurement.

=÷

=++

Pupils Length of classroom

Martin and Ahmed 9 m

Sue and Maria 9025 mm

David and Tariq 902 cm


K3 SpecialsChanging speed

1 Draw lines to match the words to the descriptions.


balanced forces

unbalanced forces

friction

Makes it difficult for things to move.

Make objects speed up or slow down.

Make objects travel at a steady speed.

2 Look at these drawings of a skater.

a On which skater or skaters are the forces

unbalanced?

b Which skater is travelling at a steady speed?

c Which skater is slowing down?

d Which skater is speeding up?

A B C


K3 SpecialsChanging speed (continued)

3 Look at these cars.

a In which car are the forces balanced?

b Which car is travelling at a steady speed?

c In which car is the engine force bigger than the friction?

d Which car is getting faster?

4 Look at this distance–time graph for a car journey.

Write A, B, or C to answer question a.

a When is the car travelling at a steady speed?

b In part A, is the car slowing down or speeding up?


friction force ofengine



C

B

A

time

distance

A

B

C


K4 SpecialsFaster!

1 Draw lines to match the words to the descriptions.


thrust

drag

air resistance

friction

Friction between a movingobject and air or water.

Pushing force of an engine.

A force when surfaces rub together.

Friction between air and a moving object.

2 All these sentences are wrong.

Find the mistake and draw a circle round it.Write the corrected sentence.

a Maximum speed is reached when thrust and friction areunbalanced.

b Air resistance and drag decrease with speed.

c Friction acts in the same direction as engine thrust.

d Smooth, sleek shapes are less streamlined than lumpy, boxy shapes.


K4 SpecialsFaster! (continued)

3 Look at these drawings. Draw circles around all thethings that are streamlined.

4 Look at this table of information about forces on amoving object.

Look at the thrust and friction. Decide if the vehiclewill have a steady speed, slow down or speed up.

Put a tick (�) or a cross (✗) in each column. Thefirst one has been done for you.


Thrust in N Friction in N Steady Slowing Speeding up speed down

250 100 ✗ ✗ �

2 3

25 25

30 20

100 100

150 250


K5 SpecialsSlow down

1 Use words from this list to fill in the gaps. You mayneed to use each word once, more than once ornot at all.


frictiondecreased increasedgravity resistance

start stop small large

a The force that slows things down is called .

b Increasing friction can moving objects.

c Brakes use friction to slow down cars.

d Parachutes use an increased air to slow things

down. They have a surface area for the air

particles to hit.

2 Draw lines to match the drawings to the descriptions.

This has a lot of air resistance. This has a little air resistance.

This has some air resistance.


K Specials answersSpeeding up

K1 Racing1 a high

b low2 distance – metres (m), time – seconds (s),

speed – metres per second (m/s)3 50 ÷ 25 = 2m/s4 50 ÷ 10 = 5m/s5 a D

b B

K2 Measuring speed1 a C (rule), mm

b A (tape), m2 a Sue, Maria

b Martin, Ahmedc i 9025 + 9029 + 9021 = 27 075 mm

ii 27 075 ÷ 3 = 9025 mm3 a smaller

b more

K3 Changing speed1 balanced forces – Make objects travel at a steady

speed.unbalanced forces – Make objects speed up orslow down.friction – Makes it difficult for things to move.

2 a A and Cb Bc Cd A

3 a Cb Cc Ad A

4 a B and Cb speeding up

K4 Faster!1 thrust – Pushing force of an engine.

drag – Friction between a moving object and airor water.air resistance – Friction between air and amoving object.friction – A force when surfaces rub together.

2 a Maximum speed is reached when thrust andfriction are balanced.

b Air resistance and drag increase with speed.c Friction acts in the opposite direction to

engine thrust.d Smooth, sleek shapes are more streamlined

than lumpy, boxy shapes.3 Circled – fish, whale, plane, boat, submarine.4

K5 Slow down1 a friction

b stopc increasedd resistance, large

2

This has a littleair resistance.

This has someair resistance.

This has a lot ofair resistance.


Thrust Friction Steady Slowing Speedingin N in N speed down up

250 100 ✗ ✗ ✓

2 3 ✗ ✓ ✗

25 25 ✓ ✗ ✗

30 20 ✗ ✗ ✓

100 100 ✓ ✗ ✗

150 250 ✗ ✓ ✗

Spe Answers.qxd 6/23/2004 9:19 AM Page 11

K1 HomeworkRacing

HELP

1 The table shows the speeds of some animals. Cheetahs, hyenas and lions are carnivores. The others are herbivores.

a i Which is the fastest animal?

ii Which is the slowest animal?

iii How far can the lion travel in one second?

iv Which herbivores are least likely to be caught by a lion?

v Explain why antelopes are less likely to be eaten by predators than zebras.

b i Hyenas mostly feed off meat that has been killed by another predator. Suggest why they do not often kill their own prey.

ii Which animal are hyenas most likely to hunt and kill?


Animal Speed in metres per second

Hyena 18

Cheetah 32

Gazelle 24

Zebra 18

Lion 23

Warthog 15

Antelope 27

K-Homework.qxd 07-Jun-04 2:03 PM Page 1

K1 HomeworkRacing (continued)

CORE

2 Use the information in the table for question 1 to answer these questions.

a How far can a cheetah run in 30 seconds?

b A warthog is 100 metres away from a lion. The lion chases the warthog. They can both run at top speed for up to 25 seconds.

i How far can the warthog run in 25 seconds?

ii How far can the lion run in 25 seconds?

iii Explain whether the lion has caught the warthog within the 25 seconds.

3 A fast human can cover 100 metres in 10 seconds.

a i How fast can a normal human run?

ii Explain why climbing a tree to escape from a lion is a better option than running away.

b John draws a distance–time graph for the human and lion.

i Describe how the two lines would look.

ii Explain what information the difference between the two lines gives you about humans and lions.

EXTENSION

4 a i It takes Tanya 22 seconds to run a 200-metre race. How fast is she running? Show how you reached your answer.

ii After some training, Tanya runs another 200 metres at 9.2 m/s. How long does she take this time? Show how you reached your answer.

b During her race, Tanya accelerates for the first 15 metres, runs at a steady speed for the next 80 metres and slows down in the last 5 metres. Tanya’s coach draws a speed–time graph for her.

Describe what would happen to the gradient of the line, on the speed–time graph, during the race.

c What would happen to the shape of the speed–time graph if Tanya could run at exactly the same speed for the whole of the race?



K2 HomeworkMeasuring speed

HELP

1 The list gives some of the units that you can use to measure the speed of objects.

a Choose the most sensible unit to measure the speed of each of the following objects.

i A human sprinter. iv A car being driven in France.

ii A car being driven in the UK. v The speed of sound.

iii A snail.

b Copy and complete the following sentences.

i When we want to compare the speeds of two objects we must use the same units because … .

ii We would need to use a stopwatch instead of a clock, to measure the time taken in a 100 metre race because … .

iii A tape measure is better than a measuring wheel, for measuring the length of a hockey pitch, because … .

CORE

2 Fatima is measuring the time it takes for her friend Tammy to run 200 metres. She istrying to find out her average speed. Fatima has recorded the following measurements.

a Which of the measurements seems to be anomalous?

b i What is Tammy’s mean speed if Fatima includes the anomalous result?

ii What is Tammy’s mean speed without the anomalous result?

iii Which of the two mean speeds is more reliable?

iv Explain your reasoning.

c i What should Fatima do to improve the reliability of her measurements?

ii Explain why this will improve their reliability.

iii Use your answer from part b ii to calculate Tammy’s mean speed over 200 metres.


centimetres per secondmetres per second kilometres per hour

miles per hour centimetres per hour

Experiment 1 2 3 4 5

Time in seconds 24.3 23.5 27.6 24.1 24.2


K2 HomeworkMeasuring speed (continued)

EXTENSION

3 Professor Spark is trying to check the speeds of some very fast chemical reactions. One of his students has already done some experiments and measured the speeds once but the professor wants to be sure about the results. He is worried about the accuracy and the reliability of his student’s measurements.

a What should Professor Spark do to make his experiments as accurate as possible?

b How will Professor Spark know that his student obtained accurate measurements?

c What should Professor Spark do to make his own experiments as reliable as possible?

d How will he know that his own measurements are reliable?

4 Kevin recorded the masses of several objects in a table.

a Which mass is the most precise?

b Which mass is the least precise?

c How could Kevin measure the mass of the car and the concrete block with the same precision?

d Explain why it is not sensible to measure the mass of a car in grams.


Object Mass

A sugar cube 3.05 g

A concrete block 1.5 kg

A feather 0.003 g

A car 0.75 t


K3 HomeworkChanging speed

HELP

1 The diagram shows a bobsleighteam at the start of their race.

a Which arrow shows the forcethat speeds up the bobsleigh?

b Which arrow shows the weightof the bobsleigh and the team?

c i Which arrow shows the forcethat slows down the bobsleigh?

ii What is the name of this force?

d In what units are all these forces measured?

e At the start, force C is larger than force A. What happens to the bobsleigh?

f i At the end of the race brakes are applied. Which force increases when the brakes are applied?

ii Explain why this makes the bobsleigh stop.

CORE

2 Look again at the diagram in question 1.

a At the start of the race force C is 300 N and force A is 20 N.

i What is the resultant force?

ii In which direction does the resultant force operate?

b One of the team members is ill. Another person who weighs 10 N more takes his place.

i How, if at all, does this affect force B?

ii Explain your reasoning.

c Halfway down the run the track starts to go uphill.

i Which force does this affect?

ii How does it affect the resultant force at that point?

iii Explain what this will do to the speed of the bobsleigh.

d Suggest a type of apparatus that you could use to measure the time taken for the bobsleigh to reach each 100 metre interval down the track.


Force B

Force CForce A


K3 HomeworkChanging speed (continued)

EXTENSION

3 Keith is going down a zip wire at a theme park. The whole slide is 100 metres long. At the start his forward force is 90 N and the friction is 45 N.

a Calculate the resultant force on Keith at the start of the slide.

b At the end of the zip wire the wire changes to horizontal.

i How does this affect the resultant force?

ii Why is the resultant force affected in this way?

iii What will happen to Keith’s speed as he approaches the very end of the wire?

c i Keith’s friend, who weighs 10 N more than Keith, is next up. In what way will the resultant force be different for Keith’s friend?

ii How will this affect the friend’s travel down the zip wire?

iii Compared with Keith, what happens to the distance that Keith’s friend travels before he stops completely?

d Both lads really enjoy the zip wire. They come back for another go later on, after it has just stopped raining. Explain how the weather will affect their speed down the wire.



K4 HomeworkFaster!

HELP

1 Use the words in the list to answer the sentences.

a This is what makes the atmosphere slow you down.

b A fish does not have much of this so it can swim quickly.

c An ice skater has this between his skates and the ice.

d Rockets get into space because of this.

e A submarine must be shaped like this.

2 The table shows some data about three cars. They are all the same weight and they all have exactly the same type of engine and the same type of tyres.

a Which car is the most streamlined?

b Which car hits the most air particles at 50 km/h?

c Some weight is removed from car C. What happens to its top speed?

CORE

3 The barracuda shown on the right is a carnivorous,tropical fish. It is one of the fastest fish in the ocean.

a i Describe how the shape of the barracuda helpsit to move through the water.

ii Explain why this shape helps it to move through water very fast.

b Explain why the barracuda needs very strong muscles in its tail fin.

c The barracuda has scales that make its skin very smooth.Explain how this helps it to swim very fast.

d i When a barracuda stops swimming it continues to moveforwards for a long way before it stops. Explain why this happens.


dragair resistance streamlined thrustfriction

Car Top speed in km/h

A 140

B 90

C 120


K4 HomeworkFaster! (continued)

ii A human wearing an aqualung stops very quickly under water.

Why does the shape of a human make them stop more quickly than a barracuda?

EXTENSION

4 Look at the diagram. It shows aworld champion skier from 1950 and another from 2004.

a Explain how the clothing of the modern skier helps her to ski faster than the 1950s skier.

b Explain why shorter skis enablethe modern skier to go fasterthan the 1950s skier.

c Skiers rub wax onto the bottomof their skis. Suggest a reason why they do this.

d i Other than friction between the skis and the snow,what force acts against both skiers to slow them down?

ii Explain why the crouching position used by a modern skier reduces this slowing force and so enables modern skiers to go faster.

e As the skis move over the snow the friction they produce melts the snow underneath each ski. Explain why this is helpful to a skier who wants to go as fast as possible.


Force B

aqualung

Force A

1950 2004


K5 HomeworkSlow down

HELP

1 Match the beginning of each sentence in the table with the correct ending. Write out each sentence.

Beginnings Endings

A Parachutes are slowed down 1 by increasing the friction on the wheel.

B Brakes slow down a bike 2 by removing the huge thrust from the engine.

C Racing cars make it easier to 3 by using the drag on their hull.travel fast

D A drag racer stops 4 by air resistance.

E Ships come to a stop 5 by being streamlined.

2 Look at the diagram of the parachutist.

a What is force A?

b i What force balances force A?

ii In which direction does this other force act?

c Which of these forces is the largest as the parachutist leaves the aircraft?

CORE

3 Look again at the diagram of the parachutist in question 2.

a Explain how air particles slow down the parachutist.

b Explain why the parachutist will fall more slowly if shehas a larger parachute.

c i If the parachutist is a much heavier person, how will this affect the speed of their drop?

ii Explain your answer.

d What can you say about the downwards and upwards forces when the parachutist is falling at a constant speed?


Force A


K5 HomeworkSlow down (continued)

EXTENSION

4 Look at the drawing of two cyclists.

a Which of the cyclists is least streamlined?

b At what point will the cyclists reach their maximum speed?Use ideas about forces in your answer.

c Using your ideas about particles, explain why cyclist Acannot reach the same speed as cyclist B, even thoughthey are on the same sort of bike and are equally powerfulcyclists.

d i What could cyclist B wear to go even faster?

ii Why would this sort of clothing help to increase hisspeed?

e Cyclist B is pedalling to provide a forward thrust of 50 N.The total friction is 10 N. Explain what is happening to his speed.


A B


K1Homework

mark schemeRacing


HELP

Question Answer Mark

1 a i The cheetah. 1

ii The warthog. 1

iii 23 metres. 1

iv The gazelle and the antelope. 2

v They can run faster than lions but zebras are slower than lions. 1

b i They don’t run as fast as the animals they eat. 1

ii Warthogs 1

Total for Help 8

COREQuestion Answer Mark

2 a 960 metres. 1

b i 375 metres. 1

ii 575 metres. 1

iii The lion has caught the warthog 1because it can run 200 metres further in 25 seconds 1and the warthog was only 100 metres ahead. 1

3 a i 10 m/s 1

ii Lions can run faster than humans (but cannot climb trees). 1

b i The gradient for the lion would be steeper than the gradient for the human. 1

ii Lions are faster than humans. 1

Total for Core 10

EXTENSIONQuestion Answer Mark

4 a i Speed = 200/22 1= 9.1 m/s 1Answer must have correct unit. Accept 9 seconds.

ii Time = 200/9.2 1= 21.7 s 1Answer must have correct unit.

b It would go up for the first 15 metres. 1It would be horizontal for the next 80 metres. 1It would go down for the last 5 metres. 1

c It would be horizontal all the time. 1

Total for Extension 8


K2Homework

mark schemeMeasuring speed


HELPQuestion Answer Mark

1 a i metres per second 1

ii miles per hour 1

iii centimetres per hour 1

iv kilometres per hour 1

v metres per second 1

b i When we want to compare the speeds of two objects we must use the same units because it makes it easier to see which is the faster. Accept alternative 1equivalent responses.

ii We would need to use a stopwatch instead of a clock, to measure the timetaken in a 100 metre race because a clock would not be precise enough. Accept alternative equivalent responses. 1

iii A tape measure is better than a measuring wheel for measuring the length ofa hockey pitch because it is more precise. Accept alternative equivalent responses. 1

Total for Help 8


2 a 27.6 s 1

b i 24.3 + 23.5 + 27.6 + 24.1 + 24.2/5 = 24.74 s 1 + 1Accept 24.7 s. Response must include correct unit.

ii 24.0 s Accept 24 s but not 24.025 s. 1

iii The second/24.0 s. 1

iv It is closer to most of the other results. 1

c i She should make more measurements. 1

ii Anomalous results are less significant/have less effect. 1

iii Mean speed = 200/24 = 8.3 m/s Accept 8.33 and correct calculations from 1 + 1carried forward error in part b ii. Unit must be correct.

Total for Core 10


3 a One from: Use a very precise measuring device/take the measurements verycarefully/repeat measurements and calculate a mean. 1

b His own results will be very close/the same as the student’s. 1

c He should do lots of measurements. 1

d All his results will be very similar. 1

4 a The feather/0.003 g. 1

b The car/0.75 t. 1

c Measure them using the same units. 1

d It does not need that level of precision/the errors would be bigger thanthe units used. Accept equivalent alternative responses. 1



K3Homework

mark schemeChanging speed



1 a C 1

b B 1

c i A 1

ii Friction/air resistance. 1

d Newtons 1

e It accelerates. 1

f i Force A. 1

ii The resultant force is now working in the opposite direction, which slows down the bobsleigh. 1

Total for Help 8


2 a i 280 N 1

ii Forwards/to the left. 1

b i It increases it. 1

ii Gravity is acting on more mass 1so the downwards force is greater. 1

c i Force C. 1

ii It reduces it. 1

iii It will stop accelerating/slow it down. 1

d A light gate 1to detect the bobsleigh as it passes each 100 metre point. 1

Total for Core 10


3 a 45 N 1

b i It reduces it. 1

ii The forward force is smaller/the friction is greater. 1

iii It will reduce/He will slow down. 1

c i It will be larger. 1

ii He will go faster. 1

iii He travels further before he stops. 1

d They will both go faster because the rain on the wire reduces the friction. 1



K4Homework

mark schemeFaster!



1 a Air resistance. 1

b Drag 1

c Friction 1

d Thrust 1

e Streamlined 1

2 a Car A. 1

b Car B. 1

c It increases. 1

Total for Help 8


3 a i It is long and thin. 1

ii It is very streamlined/the number of particles hitting the front of the fishis very low. 1

b To provide a large thrust to push it forwards through the water. 1

c This reduces drag. 1

d i It is streamlined and has low drag 1so fewer water particles collide with it as it moves. 1It continues until it has hit enough water particles to stop it. 1

ii The shape is less streamlined; so the drag is much larger 1which means there are many more particles hitting the diver/particles are 1hitting the diver over a much larger surface area than the barracuda. 1

Total for Core 10


4 a It fits much more closely/is shiny 1so the air resistance is less. 1

b There is less friction between skis and snow to slow her down. 1

c It reduces the friction between ski and snow to a minimum. 1

d i Air resistance. 1

ii Crouching gives a smaller surface area for the air particles to hit 1so the air resistance is reduced. 1

e There is less friction between water and the skis than between snow andthe skis. 1



K5Homework

mark schemeSlow down


HELP

Question Answer Mark

1 Correct matches are: A – 4; B – 1; C – 5; D – 2; E – 3 44/5 correct = 4 marks; 3 correct = 3 marks etc.

2 a Gravity 1

b i Air resistance. 1

ii Upwards 1

c Gravity 1

Total for Help 8


3 a The air particles hit the underneath of the parachute 1creating an upwards force 1that balances the downward force of gravity. 1

b It has a larger surface area 1so more air particles hit the underneath of it every second 1creating a larger air resistance. 1

c i It will increase. 1

ii There is a greater downward force to be balanced so the air resistance must 1increase and this only happens if it is moving faster. 1

d They are equal/the same. 1

Total for Core 10


4 a Cyclist A. 1

b When the resultant forward force/thrust is at its maximum. 1

c Cyclist A has a larger surface area 1so more air particles hit him every second 1making his air resistance larger than for cyclist B. 1

d i He could wear a smooth body suit/lycra clothing. Accept sensible suggestions. 1

ii It would reduce air resistance because it is smoother. 1

e He is accelerating because the thrust is larger than the total friction. 1



K Test yourselfSpeeding up

1 The table shows the time taken by five athletes to run a 100 m race.

a Complete the last column to show the order in which the athletes finished the race.

b What was Pat’s average speed?

c Was Pat’s top speed more than, less than or equal to your answer to b?

d Why would a hand-held stopwatch not give accurate enough times for this race?

2 Draw lines to match each force with its correct meaning.

Force Meaning

weight � � the force due to a moving object displacing air molecules

thrust � � a force that opposes motion

friction � � the force on an object due to gravity

air resistance � � a forward pushing force

3 Complete the following sentences. Choose from the words below to fill the gaps.

If all the forces acting on an object are balanced, the object is either

or moving at a speed.

The force of acting on an object gives

it weight. This force acts .

If an object is falling through the air, a force called

acts in the direction on it.


Athlete Time in seconds (s) Position

Jo 11.8

Pat 10.0

Chris 10.5

Nita 11.4

George 12.0

balanced constant downwards air resistance

gravity stationary upwards weight

Test-Qust.qxd 6/25/2004 10:33 AM Page 30

K Test yourselfSpeeding up (continued)

4 Look at the diagrams of a submarine. The forces acting on it are represented by arrows, and the length of each arrow is proportional to the size of the force. The submarine starts from rest.

Under each diagram, circle the word or words that describe its direction of motion when the forces shown are acting on it.

5 Modern cars are designed to have a streamlined shape so that they can go faster.

a What force does streamlining reduce?

b How does this allow the car to go faster?

c What can you say about the forces on a car when it has reached its top speed?

d Why does streamlining increase the top speed of a car?


a b

cd

up down forwards backwards up down forwards backwards

up down forwards backwardsup down forwards backwards


K Test yourselfSpeeding up (continued)

6 The diagrams show a skydiver infree fall and after her parachutehas opened.

a Show the weight of theskydiver in each diagram with an arrow labelled W.

b Show the force of airresistance in each diagramwith an arrow labelled R.

c Complete the following sentences by crossing out the incorrect words.

i Weight W increases/decreases/stays the same when the parachute opens.

ii Air resistance R increases/decreases/stays the same when the parachute opens.

iii The speed increases/decreases/stays the same when the parachute opens.

iv When weight equals air resistance, the speed increases/decreases/stays the same.

7 The distance–time graph describes the motion of a car.

a How far does the car travel in 4 s?

b Find the speed of the car during the first 4 s.

c What happens between 4 s and 6 s?

d Draw a line on the graph to show the motion of a different car that, during the first 4 s, travels at half the speed of the original car.


in free fallafter parachutehas opened

Dis

tanc

e in

met

res

(m)

0Time in seconds (s)

1 2 3 4 5 6

10

20

30

40

50

60


KTest yourself

AnswersSpeeding up

1 The table shows the time taken by five athletes to run a 100 m race.

a Complete the last column to show the order in which the athletes finished the race.

b What was Pat’s average speed?

c Was Pat’s top speed more than, less than or equal to your answer to b?

d Why would a hand-held stopwatch not give accurate enough times for this race?

2 Draw lines to match each force with its correct meaning.

Force Meaning

weight � � the force due to a moving object displacing air molecules

thrust � � a force that opposes motion

friction � � the force on an object due to gravity

air resistance � � a forward pushing force

3 Complete the following sentences. Choose from the words below to fill the gaps.

If all the forces acting on an object are balanced, the object is either

or moving at a speed.

The force of acting on an object gives

it weight. This force acts .

If an object is falling through the air, a force called

acts in the direction on it.upwardsresistance

air

downwards

gravity

constantstationary

Reaction time (stopping and starting the clock) is long compared with race time.

more than

10 m/s


Athlete Time in seconds (s) Position

Jo 11.8 4

Pat 10.0 1

Chris 10.5 2

Nita 11.4 3

George 12.0 5

balanced constant downwards air resistance

gravity stationary upwards weight

Test-Ans.qxd 16-Jun-04 2:55 PM Page 30

KTest yourself

AnswersSpeeding up (continued)

4 Look at the diagrams of a submarine. The forces acting on it are represented by arrows, and the length of each arrow is proportional to the size of the force. The submarine starts from rest.

Under each diagram, circle the word or words that describe its direction of motion when the forces shown are acting on it.

5 Modern cars are designed to have a streamlined shape so that they can go faster.

a What force does streamlining reduce?

b How does this allow the car to go faster?

c What can you say about the forces on a car when it has reached its top speed?

d Why does streamlining increase the top speed of a car?

the forces become balanced.

equal to the thrust of the engine (forwards) so the car can go faster before

The car reaches a higher speed before the air resistance force (backwards) is

(equal to the thrust of the engine).

The forces are balanced so frictional forces are at their maximum value

It gives a large resultant force forwards.

air resistance or air friction


a bup down forwards backwards up down forwards backwards

cd

up down forwards backwardsup down forwards backwards


KTest yourself

AnswersSpeeding up (continued)

6 The diagrams show a skydiver infree fall and after her parachutehas opened.

a Show the weight of theskydiver in each diagram with an arrow labelled W.

b Show the force of airresistance in each diagramwith an arrow labelled R.

c Complete the following sentences by crossing out the incorrect words.

i Weight W increases/decreases/stays the same when the parachute opens.

ii Air resistance R increases/decreases/stays the same when the parachute opens.

iii The speed increases/decreases/stays the same when the parachute opens.

iv When weight equals air resistance, the speed increases/decreases/stays the same.

7 The distance–time graph describes the motion of a car.

a How far does the car travel in 4 s?

b Find the speed of the car during the first 4 s.

c What happens between 4 s and 6 s?

d Draw a line on the graph to show the motion of a different car that, during the first 4 s, travels at half the speed of the original car.

The car is stationary/stops moving.

speed = distance

= 60

= 15 m/s_____ __time 4

60 m


in free fallW

R

after parachutehas opened

W

R

0 1 2 3 4 5 6

10

20

30

40

50

60

Dis

tanc

e in

met

res

(m)

Time in seconds (s)


KEnd of unit test

GreenSpeeding up

1 Look at the diagram of two fish, P and Q.

a Which fish, P or Q, has the more streamlined shape? 1 mark

b Explain why the more streamlined fish is able to swim faster. 1 mark

2 The diagram shows a dish on a table

a What is force A ? 1 mark

b What is force B ? 1 mark

c What can you say about the size of forces A and B ? 1 mark

d Some fruit is put into the bowl.

What can you say about the size of forces A and B now? 2 marks

3 The table below shows the times taken by four students to run 200 m.

a Who had the highest speed? 1 mark

b Who had the lowest speed? 1 mark

4 The diagram shows the forces acting on a car. It was not moving before the forces started to act.

a How big is the unbalanced force acting on the car? 1 mark

b Is the unbalanced force acting forwards or backwards? 1 mark

c Will the car move forwards, move backwards or remain stationary? 1 mark


P Q

A

B

1000 N200 N

Student Time (s)

Andy 25.4

Beth 28.9

Carl 22.6

Dhara 26.1

J-L-EUTest.qxd 18-Jun-04 11:00 AM Page 9

5 Kim lives 5 miles from school. It takes her 15 minutes to get to school.

Priya lives 15 miles from school. It takes her 40 minutes to get to school.

a Who travels at the higher average speed? 1 mark

b Kim stops at a shop for 5 minutes on her way home. What isher average speed in miles per hour for the journey home?Show your working. 2 marks

6 The diagram below shows a parachutist.

a What do we call force R? 1 mark

b What happens to the size of force R as the speed of the parachutistincreases? 1 mark

c Look at the three diagrams of the parachutist below. The longerthe arrow, the greater the force.

For each diagram, X, Y and Z, state whether the parachute isspeeding up, slowing down or falling at a steady speed. 3 marks

KEnd of unit test

GreenSpeeding up (continued)


R

X

R

Y

R

Z

R

weight, W


KEnd of unit test

GreenSpeeding up (continued)

7 Peter set up a datalogging experiment to measure the speed offalling objects. He set up two light gates and carefully measuredthe distance between them.

He dropped the ball through the light gates, and this recorded thetime it took for the ball to fall. Using the time and distance hecould calculate the speed of the ball.

a Peter said that dropping the ball once would give a reliable result.What should Peter do to get a reliable result? 1 mark

b i Name a factor that should be kept constant during theexperiment if the results are to be reliable. 1 mark

ii When Peter looked at the results on the datalogger, they were inthe form of a table. How could Peter present his results so thatthey were easier to understand? 1 mark

Peter could have done the experiment by dropping the ball andusing a stopwatch to time the ball over the same distance as inthe datalogging experiment.

The results would be much less reliable than using the dataloggerand light gates.

c i Suggest why the timing would be less reliable. 1 markii Suggest why the distance would be less reliable. 1 mark


to input A

to input B interface


KEnd of unit test

RedSpeeding up

1 The diagram shows the forces acting on a car. It was not movingbefore the forces started to act.

a How big is the unbalanced force acting on the car? 1 mark

b Will the car move forwards, move backwards or remain stationary? 1 mark

2 a Kim lives 5 miles from school. It takes her 15 minutes to get to school.

Priya lives 15 miles from school. It takes her 40 minutes to get to school.

Who travels at the higher average speed? 1 mark

b Danny cycles to school at an average speed of 8 km/h. How fast does he cycle in m/s? Show your working. 2 marks

3 The graph shows how far a cyclist travels in 10 s.

Use the graph to answer these questions.

a What was her average speed during the 10 s period? 1 mark

b Between which times was she travelling fastest? 1 mark

c When cyclists want to go fast, they often crouch down.How does this help them to go faster? 1 mark


1000 N200 N

Dis

tanc

e (m

)

0 2 4 6 8 10Time (s)

1 3 5 7 9

10

20

30

40


KEnd of unit test

RedSpeeding up (continued)

4 A model rocket takes off vertically. It has a weight of 1 N.

a The rocket motor gives it an upward thrust of 3 N.What is the unbalanced upward force on the rocket? 1 mark

b How does the speed of the rocket change, if at all, just afterthe launch? 1 mark

c The thrust of the rocket motor remains constant. As the fuel isused up, the mass of the rocket decreases.i How does this affect its motion? 1 markii Explain your answer. 2 marks

5 The diagram below shows a parachutist before he opens his parachute.

a i What happens to force R as the speed of the parachutistincreases? 1 mark

ii Use ideas about particles to explain why this happens. 1 markiii What can you say about the speed of the parachutist when

the forces W and R are equal? 1 mark

b The diagram below shows a parachutist after opening his parachute.

i What happens to force R when the parachute opens? 1 markii When the parachute opens, the parachutist slows down.

Explain why this happens by referring to forces R and W. 1 markiii Explain how R changes as the parachutist falls towards the ground. 1 markiv What can you say about the speed of the parachutist when

R becomes equal to W, compared with your answer in a iii? 1 mark


R

weight, W

R

W


KEnd of unit test

RedSpeeding up (continued)

6 Peter set up a datalogging experiment to measure the speed of fallingobjects. He set up two light gates and carefully measured the distancebetween them. He dropped the ball through the light gates, and thisrecorded the time it took for the ball to fall. Using the time and distancehe could calculate the speed of the ball.

Peter could have done the experiment by dropping the ball and usinga stopwatch to time the ball over the same distance as in thedatalogging experiment.

The results would be much less reliable than using the dataloggerand light gates.

a Suggest why the timing would be less reliable. 1 mark

b Suggest why the distance would be less reliable. 1 mark

c The stopwatch is accurate to 0.1 seconds. The datalogger isaccurate to 0.01 seconds. Which would give the most precise results? 1 mark

7 When doing research into fallingobjects, Peter found this graph. Itshows the motion of a man jumpingfrom a plane, opening his parachuteand landing on the ground.

a How many seconds passedbetween jumping from theplane and opening theparachute? 1 mark

b What was the change inspeed when the parachuteopened? 1 mark


to input A

to input B interface

0 60 120 180 240 300 360

Time (seconds)

60

50

40

30

20

10

0

Spee

d (m

/s)


KEnd of unit test

mark schemeSpeeding up


Green (NC Tier 3–6)Question Answer Mark Level

1 a P 1 3

b There is less resistance to its motion or water resistanceis less or it displaces fewer water molecules each second. 1 5

2 a Weight (of the dish). 1 3

b Reaction force or force of table on dish. 1 4

c A and B are equal. 1 4

d A and B both increase 1 5but remain equal. 1 5

3 a Carl 1 4

b Beth 1 4

4 a 800 N 1 5

b Forwards 1 5

c Move forwards. 1 4

5 a Priya 1 6

b Time for journey home = 20 minutes 1 6Average speed = 5 miles/0.33 hours = 15 mph 1 6Accept for one mark: 15 or 15 mph withoutshowing working

6 a Air resistance (force of) 1 4

b R increases 1 5

c X speeding up. 1 6Y falling at a steady speed. 1 6Z slowing down. 1 6

7 a Repeat the experiment several times andtake an average. 1 4

b i The height the ball is dropped from or thedistance between the light gates. 1 5

ii He should plot the results as a graph. 1 5

c i It would be difficult to operate thestopwatch quickly enough. 1 6

ii It would be difficult to judge the distanceaccurately. 1 6

Scores in the range of: NC Level

4–6 3

7–11 4

12–16 5

17–25 6


KEnd of unit test

mark schemeSpeeding up


Red (NC Tier 5–7*)Question Answer Mark Level

1 a 800 N 1 5

b Move forwards. 1 5

2 a Priya 1 6

b 8000 m/3600 s = 2.22 m/s 2 6One mark for working, one mark for correct answerincluding units.

3 a 4 m/s 1 6

b 0 to 4 s 1 6

c It reduces the air resistance force or it gives them less 1 7surface area.

4 a 2 N 1 6

b The speed increases. 1 6

c i It speeds up more quickly. 1 7ii The downward force (weight) is less 1 7

so there is a greater resultant force upwards. 1 7

5 a i R increases. 1 5ii As the speed increases, the parachutist displaces more

air molecules per second (so force R increases). 1 6iii The speed is constant. 1 5

b i R increases (a lot). 1 5ii R is bigger than W or R is a bigger force up than force

W is down. 1 7iii As the speed decreases, R gets smaller. 1 7*iv Slower constant speed. 1 7*

6 a It would be difficult to operate the stopwatchquickly enough. 1 6

b It would be difficult to judge the distance accurately. 1 6

c The datalogger. 1 6

7 a 180 seconds. 1 7

b From 60 m/s to 5 m/s. 1 7

Scores in the range of: NC Level

6–10 5

11–15 6

16–18 7

19–25 7*


K Pupil checklistSpeeding up


Learning outcomes I can do I can do I need to this very this quite do more well well work on this

I can describe how to calculate speed.

I can represent speed on a distance–time graph.

I can measure the speed of sound.

I can choose the most suitable measuring devices for a task.

I can distinguish between precision and accuracy.

I understand the meaning of ‘reliability’ when doing experimental work.

I can identify the forces acting on an object.

I can identify balanced and unbalanced forces.

I can calculate the resultant force.

I can use light gates and dataloggers to measure fast speeds.

I can relate the forces acting on an object to its speed.

I can explain how the air resistance of an object depends on its shape (streamlining).

I can give examples of streamlined objects.

I can explain how air resistance changes with speed.

I can describe how friction is used to slow down objects.

I can explain the motion of a falling parachutist.

I can use graphs to describe and analyse the movement of falling objects.

Pupil-Checklist.qxd 17-Jun-04 8:00 PM Page 11

K GlossarySpeeding up


Word

acceleration R

accuracy R

deceleration R

distance–time graph

drag

gradient

mean

precise

reliability

resultant force

speed–time graph R

steady speed

streamlined

thrust

unit

Definition

A standard quantity by which something is measured.

A graph that shows the speed of a moving object – thedistance travelled for each unit of time.

A graph that shows the acceleration, deceleration or steadyspeed of a moving object – the speed travelled for each unitof time. R

The slope of a line on a graph.

Speeding up. Acceleration is shown by an upwards gradienton a speed–time graph. R

Slowing down. Deceleration is shown by a downwardsgradient on a speed–time graph. R

Accurate, or as close as possible to an exact amount or detail.

How much something can be trusted. A value becomes morereliable the more times it is measured.

The average of a set of values or measurements.

How close a measurement is to its ‘real’ value. R

Not getting faster or slowing down, but keeping at the samespeed.

The size of an unbalanced force, which makes the objectmove, or speed up, or slow down.

The pushing force of a rocket or engine.

A shape of an object that allows it to move through the aireasily. A streamlined car has low air resistance.

The friction force between a moving object and the air orwater particles it is moving through.

Glossary.qxd 18-Jun-04 11:33 AM Page 12

K Key wordsSpeeding up

acceleration R

accuracy R

deceleration R


drag

gradient

mean

precise

reliability

resultant force


steady speed

streamlined

thrust

unit

Sheet 1 of 1

Sheet 1 of 1


Key wordsK Speeding up

acceleration R

accuracy R

deceleration R


drag

gradient

mean

precise

reliability

resultant force


steady speed

streamlined

thrust

unit


Keywords.qxd 18-Jun-04 11:35 AM Page 11


K Book answersSpeeding up

K1 RacingGreena Wednesdayb Carolyn’sc 10m/s1 a 100 metres

b 40 seconds2 5m/s3 0.1m/s

Reda i 0.28 m/min

ii 2096 times faster.b Set up the running track marked out in metre

intervals. Put the video camera to record bothSusan’s running on the track and a stopwatch inthe same frame. Her distance run can then becombined with the stopwatch reading to giveher speed at any point.

c i Two periods of acceleration.ii Two periods of deceleration.

1 a 10 m/sb 100 mc 40 seconds

2 a Two. There are two short sharp periods ofacceleration.

b i 0.167km/minii 10km/h

c Bd Ae C

K2 Measuring speedGreena Yes. The wheel is easiest to use for a large distance.b The stopwatch is most precise because it can

measure in hundredths of a second.c The times they were measuring were very short

times. The precision needed was withinhundredths of a second and the normal watchwould not show the times with enough precision.

1 Repeating measurements and taking a mean ...gives a more reliable value.A stopwatch is more precise ... than a clock withonly two hands.To measure speed you need to measure ... bothdistance and time.

2 84 706 seconds, 1412 minutes, 23.5 hours, a day.3 a A

b Individual answers.

Reda Yes. The wheel is easiest to use for a large

distance.b Their calculations are correct.

300 m ÷ 0.95 s = 316m/s.c Their calculations are correct.d i 72kme ii 300 000km/s

1 84 706 seconds, 1412 minutes, 23.5 hours, a day.

2 D3 a 308 m/s

b i The mean (average) value would be morereliable.

ii The value would be more precise.iii The value would be more accurate.iv The value would be more precise.

K3 Changing speedGreena i 8 metres

ii 8m/sb If he hit another player or the wall. The

backward force would be even greater.1 a You travel at a steady speed when you do not

slow down or speed up.b You slow down when there is an unbalanced

force backwards.c You speed up when there is an unbalanced

force forwards.d A distance–time graph shows a steady speed

when the line is straight with a constantgradient.

2 a 25Nb forwardsc Speeds up.

Reda The gradient (slope) of the line would be

steeper.b His acceleration will not be as great on the

second day.c Lorries have greater masses than cars and need

larger engines to produce enough acceleration.d If he hit another player or the wall. The

backward force would be even greater.e A lorry needs more force to slow it down.

The larger the mass, the harder to slow down.1 a 25N

b forwardsc Speeds up.

2 a Between 4 and 6 minutes.b Between minutes 2 and 4.c 0.1 km/mind

0.3

0.2

0.1

0 2 4 6 8 10 12Time in minutes

Spee

d in

km

/min

Book Answers.qxd 18-Jun-04 12:44 PM Page 29


K Book answersSpeeding up (continued)

K4 Faster!Greena i thrust ii Air resistance.b The air resistance balances the thrust.c They can swim very fast and escape from

predators.1 The pushing force of the engine ... increases

with speed.Air resistance and drag are ... types of friction.Friction acts in the opposite direction ... to themovement of the vehicle.Maximum speed is reached when ... thrust andfriction are balanced.Air resistance and drag are ... types of friction.

2 a A – speeding up.B – slowing down.C – steady speed.

b A, C, then B.3 The smooth surfaces reduce drag (air resistance).

Reda The faster an object moves the more air particles it

meets in a given time. The more air particles theobject hits the more the friction and air resistance.

b The thrust of the engine in a forward directionis equalled by the force of air resistance in thebackward direction.

c They can swim very fast and escape frompredators.

d When the car is streamlined the backward forceof air resistance is lower. The amount of thrustneeded to equal the reduced air resistance willtherefore be decreased.

e Less thrust requires less power from the engineand less fuel will be consumed.

1 a A – speeding up.B – slowing down.C – steady speed.

b A, C, then B.2 a Particles in the air are spread out with empty

space between them. This causes a small dragon the hydrofoil since it hits relatively fewparticles. The thrust needed is thereforerelatively small compared to the boatbecause particles in liquid water are packedclosely together. This causes a large drag andthe boat needs more thrust to be able topush through the water.

b The streamlined shape causes the air particlesto bounce off at an angle as the ‘boat’ shapecuts through the air. In the ‘boxy’ shape theair particles hit the surface flat on andproduce maximum resistance.

K5 Slow downGreena So it can go faster.b So it can stop more quickly.

c The open parachute has a large surface area andcatches a lot of air. Before it opens the skydiverhas only a small surface area and therefore asmall air resistance.

d In water the particles are very tightly packedtogether compared with air. Water particles arealso heavier than air. Therefore a large shiptravelling in water hits many more heavy waterparticles and produces much more friction thana comparatively small car hitting air particles.

1 a B, C, A.b The skydiver’s area hitting the air is least in B,

more in C and most in A when the parachuteis open.

2 a 250 mb 50 m/sc No. The distance-time graph is a straight line.

She falls the same distance each second.

Reda The racer wants to minimise the air resistance so

that the car will go faster during the race butmaximise the air resistance so the car will stopquickly.

b Event Resultant Accelerationforce

1 exits plane 1000 down accelerating2 begins fall 400 down accelerating3 free fall 0 steady speed4 parachute 1000 up decelerating

fully open5 parachute 600 up decelerating

fully open6 parachute 0 steady speed

fully openc The brake pads get very hot and the carbon is

burned off as carbon dioxide gas.1 a The air resistance of the parachutist.

b The parachutist’s weight.2 Between 5 and 19 seconds, and between 30 and

50 seconds. During both these periods the speedis constant, so the upward force is equal to thedownward force.

3 a Accelerating between 0 and 5 seconds.Decelerating between 19 and 30 seconds.

4 When the parachute is open it has a largesurface area, so it gathers in many air particleswhich slows it down. When the parachute isclosed the surface area of the parachutist isrelatively small. Fewer air particles hit theparachutist so the air resistance is small.

5 When the parachute first opens, the parachutistis falling fast. Many air particles are gathered inby the fast moving parachute and the airresistance is very high. As the parachutist slowsdown, fewer and fewer air particles are gatheredinto the parachute. The air resistance becomesless and a steady speed is reached.

Book Answers.qxd 18-Jun-04 12:44 PM Page 30

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