asking scientific questions - kerboodle · pdf fileasking scientific questions ... think ahead...

© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements This resource sheet may have been changed from the original.

Asking scientific questions

Setting the scene

Scientists ask questions before they design experiments. The answers help

them understand how or why something happens. In this activity you will

find out more about the best questions to ask.

Aims

In this activity you will be working scientifically to:

turn an idea into a question to investigate

state the independent, dependent, and control variables

decide which questions can be investigated with a practical investigation.

Task

For any investigation, you can change several things. These are called

variables.

Independent variable: what you change in an investigation

Dependent variable: what you measure to judge the effect of changing

the independent variable

Control variable: what you must keep the same

Fill in the table on the next page.


Station Ideas

(Think of three ideas)

Questions

(Choose one) Variables

1

1:

2:

3:

Independent:

Dependent:

Control:

2

1:

2:

3:

Independent:

Dependent:

Control:

3

1:

2:

3:

Independent:

Dependent:

Control:

4

1:

2:

3:

Independent:

Dependent:

Control:

Extension

1 Some questions cannot be investigated with a practical investigation.

Choose one question relating to one of the stations visited and explain

why it cannot be investigated.

2 Rewrite the question so it can be investigated with a practical experiment.


Asking scientific questions

Station Ideas

(Think of three ideas)

Questions

(Choose one) Variables

Example:

For a rubber

band

1: How far does it stretch?

2: Does it make a noise if I pluck it?

3: Can I use it to make a car move?

How far does it stretch when I apply

a force?

Independent: Force used

Dependent: Distance elastic band

stretches from its initial position

Control: Width of elastic band, type

of rubber

1 1:

2:

3:

Independent:

Dependent:

Control:

2 1:

2:

3:

Independent:

Dependent:

Control:

Remember:

Independent variable: what you change in an investigation

Dependent variable: what you measure to judge the effect of changing the independent variable

Control variable: what you must keep the same.


Planning investigations

Setting the scene

Scientists must plan an investigation to choose the best way to answer their

questions. This includes the method, how to carry out a safe investigation, and

how to collect good data.

In this activity you will find out more about planning investigations.

Aims


decide what should be included in a plan

include examples of good data

include ideas for a risk assessment.

Task

It is important to choose the right equipment to make measurements.

At each station, choose the most suitable equipment to make the

measurement described.

Take a reading, followed by two repeats.

Think ahead so you plan to work safely. This is called a risk assessment.

Draw up your own results table using the grid below.


Questions

1 Station 1: Describe how you used the equipment to measure the volume of sand.

2 Station 2: Write down three things you must do to measure the thickness of a pile

of paper.

3 Station 3: State which equipment you used to measure the size of a piece of cloth.

Give a reason.

4 Station 4: Write a simple plan for another student to follow to measure the time for

a crumpled ball of paper to drop a vertical height of 1 m.

5 Scientists often check other people’s results. Check your results with another

student. If your results are the same, your experiment is reproducible. Explain if

any of your results were reproducible.


6 If you take the same measurements several times and get the same reading, the

experiment is repeatable. Explain if any of your results were repeatable.

Extension

Suggest some risks involved in heating water using a Bunsen burner. Explain how you can

reduce these risks.


Planning investigations

Station Equipment used Reading 1 Reading 2 Reading 3

1: volume of sand

2: thickness of a pile of

paper

3: size of a piece of

cloth

4: time for crumpled

paper to fall a vertical

distance of 1 m


Collecting and presenting data

Setting the scene

Scientists collect data when they carry out experiments. The data must be recorded

clearly so scientists can use it after the experiment is finished. In this practical you

will find out more about how to collect and present data.

Aims

In this practical you will be working scientifically to:

collect data using a table

calculate means

present data as a bar chart.

Task

You will investigate this question:

Does the type of ball affect how high it bounces when it is dropped 1 m?

Choose the independent variable: type of ball/height of bounce/height it falls

Choose the dependent variable: type of ball/height of bounce/height it falls

Choose variables you will control: type of ball/height of bounce/height it falls

Type of ball Height the ball bounces (cm) Mean of height the

ball bounces (cm) First reading Repeat reading

Carry out the experiment and record your readings in your table.

Work out the mean of your results.

Questions

1 Why did you drop the ball from the same height each time?


2 Draw a bar chart to display your results in the grid below.

3 State if you can see a pattern in your results. Describe this pattern.


Collecting and presenting data

Setting the scene

Scientists collect data when they carry out experiments. The data must be

recorded clearly so scientists can use it after the experiment is finished. In this

practical you will find out more about how to record and present data.

Aims

In this practical you will be working scientifically to:

collect data using a table

calculate means

choose the best way to present data.

Safety

Try not to let balls roll on the floor.

Do not throw balls.

Equipment and materials

metre ruler

four different types of balls, as chosen by your teacher

Method

In this practical you will investigate this question:

Does the type of ball affect how high it bounces when it is dropped 1 m from the

ground?

Write down the independent variable:

Write down the dependent variable:

Write down variables you will control:

Carry out the experiment using four different types of balls provided.

Record your results in the table on the next page.


Results

Include a column for the independent variable.

Include three columns for the dependent variable – you will repeat readings.

Include a column for the mean of the readings.

Each column heading includes the name of the variable and its unit.

You need one row for each value of the independent variable.

Calculate the mean for your results.

Questions

1 State whether the data for your independent variable is continuous or categoric.

2 State whether the data for your dependent variable is continuous or categoric.

3 State the type of graph/chart you should draw to present your data. Explain your

answer.


4 Draw a graph/chart of your results in the grid below.

Remember: The independent variable should be on the x-axis and the

dependent variable should be on the y-axis.

5 State if you can see a pattern in your results. If there is a pattern, describe this pattern.

Extension

Suggest a reason for the pattern in your results.


Analysing data

Setting the scene

Scientists design experiments to answer a question. Once they have the data,

they must analyse it so they can explain if there is a relationship. In this

activity you will find out how to analyse data from experiments.

Aims


plot graphs

use graphs to describe a relationship

describe stages in stating a relationship between variables.

Task

Plot a graph for each table of data using the grids provided.

o A scatter graph or line graph are best when variables are continuous (can have any value).

o Choose the scale so the numbers go up in equal steps.

o The independent variable is in the first column and goes on the x-axis (horizontal axis).

o Plan ahead so the numbers you plot fit on the graph’s axes.

o Don’t forget labels and units for both axes.

o Plot the points on the graph.

o Draw a straight line that goes as close to all the points as possible.


Table 1

Volume of water (cm3) Height of water in measuring

cylinder (cm)

20 2

40 4

60 6

80 8

100 10

Graph 1


Table 2

Angle of incident light ray (°) Angle of reflected light ray(°)

10 12

20 20

30 28

40 42

50 50

Graph 2


Table 3

Force used (N) Length of rubber band (cm)

1 10.0

2 11.1

3 12.0

4 12.8

5 14.2

6 15.8

7 17.1

8 18.0

Graph 3


Describe the relationship each graph shows in as much detail as possible.

Graph 1

Graph 2

Graph 3

Questions

1 Give another example of data you could plot on a line graph or a scatter graph.

2 Give an example of data you could plot on a bar graph.

3 Describe the stages you must follow to analyse data and describe a relationship.


Extension

1 Plot this data on a scatter graph using the grid provided.

You do not need to start the scale for the y-axis at zero.

Table 4

Cooling time (s) Water temperature (°C)

0 80

60 71

60 66

90 63

120 57

150 55

180 53

210 51

240 50

Graph 5


2 You cannot draw a straight line of best fit for this data. Explain how you choose the

line of best fit.

3 Describe the relationship this graph shows. Use numbers to support your answer.

© Oxford University Press 2014 This resource sheet may have been changed from the original.

Analysing data Use the following labelled graph grids to plot your data.

Graph 1

Graph 2


Evaluating data

Setting the scene

Scientists evaluate data from an experiment to see if it is good enough to

answer their question.

In this activity you will find out how to evaluate data from experiments.

Aims


describe how to evaluate data

suggest ways to improve the data from an experiment.

Task

Here are two accounts written by students who wanted to know how far a

table-tennis ball, squash ball, tennis ball, golf ball, and billiard ball travelled

when hit using a tennis racket.

Read each write-up.

Experiment 1

o I bounced the table-tennis ball, the squash ball, and the tennis ball, then hit them. I threw the golf ball and the billiard ball in the air, then hit them.

o Some strings on the tennis racket broke when I hit the billiard ball but I carried on. I stood in different places after the billiard ball broke a window. I tested the tennis ball three times and the other balls once.

o The tennis ball went furthest. I decided this by looking. I think my test went well.

Experiment 2

o I tried bouncing the balls but it didn’t work for all balls. So I threw each ball up and hit it hard but it broke the tennis racket.

o I used a new racket and threw each ball in the air and hit it medium

hard. I practised a few times. Then I took a new set of results and tried each ball three times.

o I stood in the same place each time and measured the distances with a

tape measure. I calculated the mean of the results.

o The tennis ball went furthest. I think my test went well.


Summarise the key differences between the experiments in the table below.

Experiment 1 Experiment 2

Questions

1 Describe the stages each student must do to evaluate their data.

2 State which experiment gave better results. Explain your answer.

3 Suggest three ways to improve the first experiment.


Extension

1 From the three suggestions that you have given in Question 3 above, explain which

change would improve the data most.

2 Explain why it is important to evaluate data carefully.


Evaluating data Read the two different methods for the same investigation.

Experiment 1

o I bounced three balls and hit them.

o I threw two balls in the air and hit them.

o I broke the tennis racket strings but carried on with my experiment.

o I stood in different places.

o I tested the tennis ball three times and the other balls once.

o I decided which ball went furthest by looking.

Experiment 2

o I threw each ball in the air and hit it medium hard.

o I changed the tennis racket after I broke it.

o I tested each ball three times.

o I stood in the same place each time.

o I measured the distances with a tape measure.

o I calculated the mean of the results.

Summarise the key differences between the experiments in the table below.

Experiment 1 Experiment 2

asking scientific questions - kerboodle · pdf fileasking scientific questions ... think ahead...

Documents