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PAGE 2 ___ THE UNIVERSE & OUR CHANGING EARTH_____________________________

Teachers Guide YEAR 8 SCIENCE Scotch College

SCOTCH COLLEGE SCIENCE

YEAR 8 Astronomy & Our Earth

OUTLINE

This unit looks at some of the more familiar objects in our solar system. You will study the stars,specifically our Sun and how it provides us with energy and our seasons. We will also look at themoon and other heavenly bodies such as asteroids. The science of geology is introduced by looking atour Earth, how it was formed and is constantly changing. You will investigate the different types of rocks that

occur on the earth and find out how and where they form.

At the end of this unit you should be able to:

Understand how the Sun provides energy for our world.

Understand what causes sunspots and solar flares. Understand how the Sun causes the seasons.

Recall the characteristics of the moon and its surface.

Explain the cause of the phases of the Moon.

Explain the effect of the Moon on the tides.

Understand what is meant by a meteor, a comet and a planet.

explain what sedimentary rocks are, and the difference between types of sedimentary rock egconglomerate, sandstone, and mudstone.

explain how sedimentary rock layers form following erosion and deposition.

describe the conditions in which each type of sedimentary rock will form (eg fast moving river, deeplake).

explain the consequences of the folding of sedimentary rock.

explain what igneous rocks are, and the difference between types of igneous rock, such as obsidian,granite and basalt.

describe the conditions in which each type of igneous rock will form (rate of cooling ofmagma/lava).

distinguish between a sedimentary rock and an igneous rock under a microscope.

explain what metamorphic rocks are, and how they form.

recall that slate and marble are metamorphic rocks formed from mudstone and limestonerespectively.

describe the processes that occur in the rock cycle.

work out the geological history of the area from a block diagram (ie a cross-section showing thearrangement of rock layers in the ground) or similar information.


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THE UNIVERSE & OUR CHANGING EARTH PAGE 3

Scotch College YEAR 8 SCIENCE Teachers guide

SCIENCE AND THE UNIVERSE

How big is the Universe, how old is it, how was it formed, what will happen to it? These are questions which

astronomers and cosmologists try to answer. There are no simple answers and any answers suggested cannot be

proved. At this stage, many different answers (or theories) have been put forward.

To try to put a scale to the universe defies imagination. Distances, and the time taken to travel them, are so great

that they become meaningless.

Scientists have put forward many models of the Universe in attempts to explain how it could have formed.

Although no one model can be said to be proven, some have been more convincing than others.

Q1. What is the current most convincing scientific theory regarding the origin of the Universe?

EXPERIMENT 1: TWINKLE, TWINKLE, LITTLE STAR!

4 groups

Aim: to investigate why stars twinkle.

Discussion:

1. What do you notice about the foil image when the water is calm?

2. What happens to this image when the water is turbulent?

3. How is the light affected as it travels from air straight down through calm water?

4. Is our view of the night sky in any way distorted? Explain your answer

Conclusion:

Light from the star travels through the vacuum of space, in a straight line. When it enters the Earths atmosphere

and hits the air currents, which have been stirred up by the heat of the Sun, the light gets bent slightly in different

ways and appears to twinkle to the observer.

Method:

1. Half fill a pneumatic trough with water2. Lightly crinkle a sheet of aluminum foil with your hands then open it up again.3. Place the foil on the table and place the tank on the foil.4. Darken the room and shine a torch down into the water.

5. Place your head next to the torch and look at the reflected light.6. Stir up the water gently and see what happens to the image.


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Q 1. There appear to be several paths for the life cycle of a star. What is the major determining factor asto which path the stars follow?

The path followed depends on the mass of the original star.

Q 2. Draw a simple flow chart showing how the pictures shown (A-I) should be arranged according tothe different life-cycle paths.

H B G A C

AND

H E F D I

Q 3. Write a paragraph or two describing the sequence of star formation, life cycle and death. collapse of a hydrogen cloud, generating high temperature the star isborn when fusion of its hydrogen fuel begins when the hydrogen fuel is depleted the star contracts

then, depending on the mass of the star:

For small stars this contraction causes a temperature increase that starts further fusion (of helium etc) and this causesthe star to swell to a red giant. Eventually the star runs out of useable fuel and contracts. The heat generated by thecontraction blasts off the suns outer layers to form a nebula, and the very hot white dwarf star left behind glows for awhile before finally dying.

For very massive stars several cycles of contraction and expansion can occur before the final collapse generates so muchheat that the star explodes (actually implodes) as a supernova. This scatters all sorts of material into space and

leaves behind a very dense object such as a neutron star or a black hole.

Q 4. Use the Internet to find out: exactly what is a black hole?A black hole is a region of space resulting from the collapse of a star. It has an extremely high gravitational field so

strong that the escape velocity exceeds the speed of light


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GALAXIES

Often, a point of light in the sky is not a star but a group of stars. The single point could be a far-off galaxy with

thousands of millions of stars in it.

CLASSIFICATION SCHEME

Nocorrect answers. Classification criteria should come out of discussion.

Galaxies are some of the most beautiful and intriguing objects in the night sky. They are also the leviathans of the

Universe, spanning tens to hundreds of thousands of light years in size. Yet we know little about how they

formed and developed over cosmic time into the objects we see today. The problem with galaxies is, every galaxy

looks different. What we would really like is to categorize galaxies in a way that gave us some insight into the

physics that made these objects become what they are.

One way of classifying galaxies is by their shape. We can tell this from the visible light they send to Earth.

Another way is to look at the spectra of the non visible radiation they send to Earth.

These are the images of nine near galaxies:

A B C

D E F

G H J

Credits: CCD Images (Bj or g band) from Frei et al. (1996)


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Your task it to take these 9 images and sort them, by eye, according to some criteria which will become your

classification scheme. In the results table list the galaxies you grouped together and the reason you classified

them this way.

Galaxies Criteria for classification

criteria could include spirality, symmetry, smoothnessIt doesnt matter the discussions the important thing.

Q 5. What problems could occur with a classification scheme based on visual observations such as this?Problems occur with visual classification schemes because of clarity of image, different interpretations of descriptions etc.

Q 6. Edwin Hubble developed a galaxy classification scheme consisting of four types: elliptical(show no spiral character)

spiral(outstretched curving arms)

barred spiral(spiral structure butwith prominent bar through

nucleus)

irregular (collection of stars withno obvious order). How do you

think this scheme compares to

your schemes.


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OUR SOLAR SYSTEM

The fact that our solar system contains considerable quantities of

elements heavier than iron indicates that it condensed from a

cloud of gas and dust produced elsewhere in a supernova.

Everything on earth air, soil, oceans, plants and animals is

made of elements produced billions of years ago by an exploding

star in an unknown corner of our galaxy.

Our solar system is believed to have been formed 5 billion years

ago from a swirling gas cloud. Most of the material accumulated

at the centre to form the Sun, but some material settled in orbits

as planetesimals, which ultimately collided and formed the

planets and their moons.

WHAT MAKES A PLANET A PLANET?

The solar system is made up of 8 planets and their associated moons, asteroids, comets, dust andgas. The planets, asteroids and comets travel around the Sun along nearly circular orbits in ananticlockwise direction.

The order of the planets from the Sun is..

What makes a planet a planet?

On August 24th, 2006 the International Astronomical Union redefined the word planet. This newdefinition meant that Pluto, which we had always considered to be a planet, no longer fits thedefinition and so instead of 9 planets in the solar system we now have 8.

Read the following articles about the demotion of Pluto as a planet.

Video calledBye, Bye Pluto is available on Clickview which would be suitable for discussion on this topic.


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Farewell, Pluto we thought the world of youStephen CauchiAugust 26, 2006

THE

WORLD

is

coming

to

grips

with

the

news

that

Pluto

is

a

planet

no

more.

Thursday'sdecisionbytheInternationalAstronomicalUniontostripPlutoofitsplanetarystatus,heldsinceitsdiscoveryin

1930,hassaddenedthosewithasentimentalattachmenttoit.Butmostastronomersapplaudthedecision.

"TheproblemwithPlutoisthatithastremendousemotionaloverload,abitlikePrincessDiana,"saidRossTaylor,aplanetary

scientistattheAustralianNationalUniversity.

"It'sgotWaltDisneyandPlutothedog,Pluto,godoftheunderworldThewholething'sgotthistremendoussentimental,

historical,emotionalkindofattachment."AuthorDavaSobel,theonlynonscientistonaunioncommitteeofsevenlastmonth

chargedwiththetaskofdefiningwhatshouldbedeemedaplanet,agrees.

MsSobel,authorofThePlanets,whoisinMelbourneasaguestoftheMelbourneWriter'sFestival,hasbeeninundatedwithemotionalemails.

"Pluto,"shewrites,"retainsanemotionalholdonplanethood.PeoplelovePluto.Childrenidentifywithitssmallness.Adults

relatetoitsinadequacy,itsmarginalexistenceasamisfit.

"AnyoneaccustomedtoaquotaofnineplanetsanyoneaversetochangesinthestatusquobaulksatdisqualifyingPluto

onatechnicality."

HercommitteecameupwithadefinitionthatkeptPlutoin,butisnotoverlyworriedbyitsdemise,whichhasbeenslowand

painful.WhenPlutowasdiscoveredin1930,astronomersthoughtitwasamediumsizedplanet,likeEarth.

Bythelate1970s,theyrealiseditwastinyadiameterof2300kilometres,afifthofthatofEarth.Itwasthesmallestplanet

inthesolarsystem,smallerthanmanymoons,includingEarth'smoonandfourofJupiter's.

Itisnotthefirsttimeastronomershavedowngradedaplanet.In1801,Cereswasproclaimedaplanetwhenitwasdiscovered,

butabout50yearslateritwasconsideredalargeasteroid.Lastyear,astronomersdiscoveredadwarfplanetnicknamed

XenathatwasslightlybiggerthanPluto.

Thisforcedadecision.EitherXenawasaproperplanet,orPlutowasadwarfplanet.

Thedecisionbytheunion,whichforthepasttwoweekshasbeenmeetinginPrague,wasnotwithoutcontroversy.Lastweek,

aunioncommitteeurgedavotetheotherway.

ThiswouldhavemeantPluto,XenaandtwootherdwarfplanetsCeresandCharonwouldhavebeenclassifiedasproper

planets,bringingthesolarsystem'stotalto12.

Underthisdefinition,aplanetwasanyobjectthatcircledthesunandwaslargeenoughtoberound.Underthenewdefinition,

anobjectisaplanetifitistheonlylargebodyinitsorbit.TanyaHill,curatorofastronomyatMelbournePlanetarium,was

anothersupporter."Icertainlyagreewiththedecision,"shesaid."Idolikethechangesthey'vebroughtaboutinthenew

resolutionbecauseitveryclearlysetsupoureightclassicalplanetsandthenthedwarfplanets."

Notallastronomersarewonover."Theyshouldhavegonewithsomethingclean,likeasizecriterion,"saidKarlGlazebrook,

fromJohnHopkinsUniversityintheUnitedStates."Seemstomelikeamuddledcompromise."

Source: The Age- online Accessed: 21sh January 2010


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QUESTIONS:

1. When was Pluto discovered?

2. List the three conditions which must now be satisfied by a planet.

3. Give two reasons why Pluto is no longer a planet.

4. What is Plutos largest moon called?


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5. Name the icy object discovered in 2003 that started the controversy regarding the definitionof a planet.

6. Name the asteroid that was considered a planet until 1801.

7. There are now only 8 known planets orbiting the Sun. Write a mnemonic (eg My VeryExcellent Memory Jogger Sadly Useless Now) to help you remember them.

8. This is a cartoon aboutPlutos demotion design one of your

own in the box belowor usewww.toondoo.com


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THE DIFFERENCE BETWEEN COMETS, METEORS AND ASTEROIDS

This task can be used as research or discussion with the class

Add the characteristics listed below to the appropriate location in the Venn diagram.


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ACTIVITY (RESEARCH): HOW DOES EARTH COMPARE TO THE OTHER PLANETS?

Our Solar system consists of eight planets which orbit the Sun. Each has its own characteristics which distinguish

it from the others. However there are some similarities.

Begin by watching the Video: The Nine PlanetsOn the Unit DVD -

1. Fill in the grid with information on each of the planets. The following websites might be a good place to start:

http://seds.lpl.arizona.edu/nineplanets/nineplanets/nineplanets.html

http://www.windows.ucar.edu/tour/link=kids_space/distance.html

2. Complete the PowerPoint template Space Explorer and insert the hyperlinks to make it active.

3. Now that you have explored the solar system, use the information gained to answer the following questions:

Q 11. What keeps the solar system together?The Suns strong gravitational effect holds the solar system together.

Q 12. How can an observer from Earth distinguish planets from stars?The planets move more quickly across the sky in relation to the stars and hence change position over time.

Q 13. List 5 major differences between Earth and the other planets.5 major differences between Earth and other planets size, atmosphere, gravity, water, life etc

Q 14. Which planet is most likely to sustain life as we know it and why?The planet we believe is most likely to sustain life is Mars due to temperature, gravity and presence of water (albeit frozen).

Q 15. If light travels at 299,792 kilometres (186,282 miles) per second, how long does it take light to reachthe Earth?

Light takes 8 min to reach Earth.

Q 16. Which planet has the most number of moons? What factor about the planet can explain this?[Students will have many different answers for this and it is a good time to point out the value of looking at the date of a website they

get information from]

According to this website http://www.spacetoday.org/SolSys/Moons/MoonsSolSys.html (2003) Jupiter has the most with 61, but they

may find a more up to date site. This is due to the large gravity of the planet.

Q 17. Some astronomers believe there is another planet referred to as Planet X. What evidence are theyforming their belief on?

http://www.foxnews.com/story/0,2933,114178,00.html

There is evidence that two scientists found a body they called Sedna beyond Pluto which could be the other planet. It orbits the sun every

10,500 years. However the definition of a planet is still a bit woozy and so there is controversy as to what it exactly is.


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THE MOON (Chap 4 in Spacefiles DVD- Inner Solar system)

Watch the DVD The Moon and answer the following questions:

1. How was the Moon formed?

Moon was formed by collisions of Earth with another body about the size of Mars.

2. How long is the lunar day ie the time for one rotation?

The lunar day is 271/3 days (28 Days)

3. How big is the Moon compared to Earth?

The Moon issize of Earth

4. What causes the phases of the Moon?

The Sun shines on the surface of the Moon and we see that reflected light. As the Moon passes the Earth it casts a shadowand we can sometimes only see part of the surface.

5. What do we call the dark patches on the Moon and what causes them?

They are called craters and are caused by meteors having collided with the surface.

6. Why dont the craters on the Moon erode?

Since there is no wind or rain on the moon there is nothing to erode the craters.

7. What type of experiments did the astronauts perform on the Moon.

The astronauts collected rock samples and did some experiments to show that a hammer and a feather fall at the same rate

without air resistance.

8. What causes the tides?

The Moon pulls on the waters of the Earth causing 2 high and 2 low tides per day. There is also an effect of the

gravitational force of the sun.

9. Why is the Moon moving away from the Earth?

The moon is moving away from the Earth due to tidal drag.

10.What would be the effect on the Earth if we lost the Moon altogether?

If the Moon was lost the Earth would wobble on its axis and become unstable. This would affect the climate and cause the

deserts to cool sometimes and ice to form at the equator sometimes.


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ACTIVITY: HOW BIG IS THE MOON?

About twice a year the Moon is eclipsed

by the Earth. This means that the Earth

passes between the Sun and the Moon

and casts a shadow on the Moon. The

Earths shadow is divided into twosections: thepenumbra, from which a

portion of the Sun could be seen, (if you

were in the Moon), and the umbra where

the Sun is totally eclipsed by the Earth.

The diameter of the Earths umbra is almost exactly the same as the Earths diameter because the Sun is so far

away. If we know that the actual diameter of the Earth is 12, 750km, we can use this shadow to estimate the size

of the Moon.

1. The shadow shown on the moon is part of the circular shadow cast by theEarth. Part of the edge of this circular shadow is shown by the dotted line.

2. Estimate the diameter of this circular shadow in cm.

3. Measure the diameter of the image of the Moon in cm.

Diameter of Earth shadow image (cm) ~ 9 12 cm

Diameter of Moon image (cm) ~ 3.0 cm

Diameter of Moon =diametershadowEarths

diameterimageMoonsx Earth diameter (km)

= about (3.0/12.0 x 12750) = ~ 3200 km (actual diameter is 3476 km)

Extension (Try this at home on the next clear night with a near full moon)

Hold a ten cent piece in front of you until it just obscures the Moon. Measure the distance from your eye to the 10

cent piece. Use the diameter of the Moon you calculated previously to work out the distance from the Earth to the

Moon.

10centpiece Moon


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How does Earth interact with the Solar system?

The Sun is the centre of our solar system and is vital to life on Earth. Solar energy from the Sun provides both

heat and light. The tilt of the Earths axis creates the seasons. Night and day is created by Earths 24-hour rotation

on its own axis. The pull of the Suns gravity is responsible for keeping all of the planets orbiting around it.

Gravity from the Sun and Earths Moon also controls ocean tides on Earth.

THE SEASONS

See the PowerPoint on Astronomy for an animation of how the seasons work or demonstrate it with tennis balls

The Seasons of the year Summer, Winter, Autumn and Spring are caused because the Earth tilts onits axis as it revolves around the Sun.

CHOOSE THE WORD FROM THE WORDLIST TO COMPLETE THE STORY ABOUT THE SEASONS.

It is all due to the way the Earth spins on itsaxiswhile it travels around the sun each year. We wouldnt

have any seasons at all if the Earths axis was straight up and down. But because the Earths axistilts,

the amount of sunlight each part of the Earth gets, changes each year.

There are fourseasonsduring the year: summer, autumn, winter and spring. When it is summer south of

the equator, it iswinternorth of the equator. That is because the South Pole is pointedtowardsthe Sun and

the North Pole is pointedawayfromthe Sun. During the summer, the rays of the Sun are more direct and

the days arelonger. During winter the days areshorter. When daylight saving comes in during thesummer

we add an hour to the clock time. Duringwinterwe subtract an hour to get back to real time.

The longest day of the year south of the equator is calledsummersolstice. This occurs in the month of

December. The days ahead are hot and great for swimming. The shortest day is called thewintersolstice.

Each day from the summer solstice to the winter solstice gets a littleshorter.

Halfway between each solstice is anequinox. On those days, the daylight and night are both 12 hours

long. In spring, at the vernal equinox, the sunrisesat the South Pole for the first time in six months. The

Poles have six month long days and nights.

Longer shorter winter summer axis rises sets tilts seasons

toward away from summer solstice Winter equinox spring

autumn December June winter solstice


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Earth Moon

Gravitationalpullofthe

moon

PHASES OF THE MOONThe PowerPoint has an excellent simulation of this or you can use a torch, ball and basketball as a

demonstration.

The phases of the moon are caused by the relative

positions of the earth, sun, and moon. The sun

always illuminates the half of the moon facing the

sun (except during lunar eclipses, when the moonpasses thru the earth's shadow). When the sun and

moon are on opposite sides of the earth, the moon

appears "full" to us, a bright, round disk. When the

moon is between the earth and the sun, it appears

dark, a "new" moon. In between, the moon's

illuminated surface appears to grow (wax) to full,

then decreases (wanes) to the next new moon. It

takes the moon approximately 28 days to rotate

around the Earth. We see the moon because it

reflects the light from the sun. However we cannot

always see the whole face of the moon because we are seeing it from different angles.

The main phases of the moon appear below:

TIDES

Tides are caused by the gravitational interaction between the Earth and the Moon (and to a lesser extent thesun as well). The gravitational attraction of the moon

causes the oceans to bulge out in the direction of the

moon. Another bulge occurs on the opposite side. Since

the earth is rotating while this is happening, two tides

occur each day.

Spring

tides areespecially strong

tides (they do not

have anything to

do with the

season Spring).

They occur when

the Earth, the Sun,and the Moon are in a line. The gravitational forces of the Moon and the Sun both

contribute to the tides. Spring tides occur during the full moon and the new moon.

Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are

perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons.


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ACTIVITY: MOON AND TIDES

There is a definite relationship between the moon and the tides, but what exactly is it? Is it possible to predict the

tides if you know the phase of the moon? In order to answer this question you will graph data concerning the

fraction of the Moon illuminated by the sun over a period of time. You will plot this against data concerning the

change in sea level for the same period of time to determine if there is a relationship between the phases of theMoon and changes in sea level.

First well graph some data showing how the fraction of the moon illuminated changes over time.

1. Open the Excel spreadsheet Moon and Tides

2. Complete column C by classifying the phase of the moon according to the amount of lunar illumination eg cell C4 is NewMoon (see data table).

3. Highlight columns A, B and then hold the Control key and highlight column D

4. Draw an XY scatter graph with a line of the data in Column A, B and D labelling the axes and display it as a separatesheet. The tide graph will be displayed as well as the moon graph.

Now add images to the data points on the chart to represent the different phases of the Moon. This will assist youin identifying and analysing patterns.

5. Click on the worksheet tab.

6. Determine the Moon image that best represents the data points on your chart.

7. Select an appropriate Moon Image.

8. From the Edit menu, choose Copy (or Copy).

9. Go to your chart. From the Edit menu, choose Paste.

10.Drag the Moon image to the data point that it best represents.

11.Repeat this for the other main Moon phases.

(You do not need to format every point, but do enough for a pattern to becomeapparent).

Is there a relationship between the phases of the Moon and the tides? One way to look for relationships between

two sets of data is to plot them against each other. To add the tidal data to the chart you have created carefully

follow these steps.

ANALYSIS. Use your graphs to help you answer the following questions.

MOON PHASE PLOT

Q 1. What happens to the fraction of the Moon illuminated as you move from left to right on the chart?More of the moon illuminated and then less.

Q 2. What is the amount of time between one new Moon phase and the next?28 days

Q 3. On what date does the highest fraction of illumination occur? With which Moon phase does thiscorrespond?

18th Jan full moon

Q 4. When do you think the next maximum illumination phase will occur?28 days later 15th Feb


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PLOT OF CHANGES IN SEA LEVEL

Q 5. Describe the shape of the line that represents the changes in sea level.The graph is sinusoidal.

Q 6. What is the amount of time between two consecutive high peaks?The time between two successive high peaks is about 11.5 hours

Q 7. When during the month do the largest changes in the sea level occur?The beginning of the month and the middle of the month

COMBINED PLOTS

Q 8. At what phase(s) of the Moon is the change in sea level the greatest?Full moon and new moon

Q 9. What phases correspond with the smallest changes in sea level?Waxing and waning gibbous moon

Q 10. Do you think there are relationships between the changes in sea level and the phases of the Moon?If so, what are the relationships?The closer the moon is to full or new, the larger the tide differences. This corresponds to alignment of the Earth Moon and

Sun.

As an extension, research and develop responses to the following:

Q 11. What is the name given to the tides that occur when the change in sea level is the greatest?Tides which occur when the change in sea level is the greatest are spring tides

Q 12. What is the name given to the tides that occur when the change in sea level is the least?Least change sea levels are neap tides

Q 13. Why are tides important?Tides are important to shipping, rock pool animals etc

Q 14. Why do you think people keep track of the tide levels at various locations around the world?Keeping track of tide levels is important for entering harbours, surfing etc.

Q 15. How might the Moon and tides affect sea life in the world's oceans?Tidal exposure of rock pool animals and coral

Q 16. What other natural events do you think might affect the sea level?Melting of icecaps, greenhouse would effect sea levels.


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ROCKETS

A rocket in its simplest form is a chamber enclosing gas under pressure. A small opening at one end of the

chamber allows the gas to escape and so provides the thrust to propel the rocket in the opposite direction. The

Science of rocketry began with a book published in 1687 by Sir Isaac Newton. He described three laws which

govern the motion of objects.

Newtons First Law

Objects will stay at rest and objects will stay in motion in a straight line unless acted on by an unbalanced force.

Q 1. Explain how a rocket sent to Pluto can carry enough fuel for the journey.The engines are switched off once the craft is in motion. Once it is moving it continues to move until a force acts on it to

stop it.

Newtons Second Law

Force is equal to mass times acceleration F = ma

Q 2. A 10kg body has an acceleration of 2m/s2. What is the net force acting on the body?F = ma = 10 x 2 = 20kgm/s2 = 20 Newton

Q 3. An empty truck with a mass of 2500kg has an engine that will accelerate at a rate of 1.5m/s2. Whatwill be the acceleration when the truck has an additional load of 1500kg?

F = ma = 2500 x 1.5 = 3750 N produced by the motor

With the extra mass: a = F/m = 3750/(2500+1500) = 0.94 m/s2

Q 4. If a 2000kg van takes 10 sec to accelerate from 20 40 m/s, what force is being applied?gain of 20 m/s over 10 seconds, so a = 20/10 = 2 m/s2

F = ma = 2000 x 2 = 4000 N

Q 5. A 2 kg mass experiences a gravity force of 19.6 N. What will be its acceleration when dropped outof a second-storey window?

a = F/m = 19.6 / 2 = 9.8 m/s2

Q 6. A motorbike engine produces a net force of 1300 N, causing it to accelerate at 6.5 m/s2 . What is themotorbikes mass?

m = f / a = 1300 / 6.5 = 200 kg


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Newtons Third Law

For every action there is always an equal and opposite reaction.

Q 7. On the diagram mark in the action force and the reaction force. Why does the skateboard travel

further than the rider when he jumps off?

The skateboard is lighter conservation of momentum

EXPERIMENT 2: SODA CAN ENGINES

Students need to supply their own can so may need to give them some warning.

1. Lay a soda can on its side and punch a small hole in the near the bottom with a nail.

2. Push the nail to one side to bend the metal, making the hole slant in that direction.

3. Rotate the can approximately 90o and make a second hole with the slant in the same direction.

4. Repeat this procedure twice more to make four equally spaced holes.

5. Bend the cans opener lever straight up and tie it to a 40-50cm fishing line.

6. Dip the can in water tub until it fills and suspend it by the fishing line.

Q 8. Why do the cans start spinning?

Q 9. Which of Newtons Laws explains this phenomenon?

Q 10. What would happen if you increased the number of holes? Try it and explain your result in termsof Newtons laws.

Q 11. What would happen if you decreased the size of the holes? Try it and explain your result in terms ofNewtons laws.

Q 12. Compare the way rockets change direction in space with the results of this experiment.


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EXPERIMENT 3: CONTROLLED PROPULSION

Students to work in groups of 4

A balloon can be used to simulate how a rocket engine works. The distance the balloon will travel in a straight

line is related to the amount of air trapped inside the balloon when it is released. This experiment will allow

you to investigate this relationship.

FORMULAE:

Volume of a sphere V = 1/6 x x (diameter)3

Circumference of sphere C = x diameter

1. Cut a piece of fishing line approximately 7m long.

2. Slide a drinking straw onto the line.

3. Blow up a balloon and hold it so that no air escapes.

4. Measure the circumference when it is fully inflated using a small piece of fishing line and enter the results in thetable.

5. Have two people hold the line taut and level.

6. Tape the balloon onto the straw with two pieces of tape the neck of the balloon should be parallel to the string.

7. Pull the balloon to the end of the line and mark the string.

8. Release the neck of the balloon and measure the distance the balloon travels.

9. Repeat steps 3-8, filling the balloon with different amounts of air, measuring the circumference as before.

Amount of Air Circumference(cm)

Diameter(cm)

Volume ofballoon

(cm3)

Distance travelled(cm)

Full

full

Half full

full

Q 13. What conclusion can be made from these results and how does this relate to Newtons Third Law.

ROCKETS AND NEWTONS LAWS

An unbalanced force must be exerted by a rocket to lift off from a launch pad or for a craft to change speed or

direction (First Law). The amount of thrust (force) produced by a rocket engine will be determined by the rate

at which the mass of the rocket fuel burns and the speed of the escaping rocket (Second Law). The reaction, or

motion, of the rocket is equal to and in the opposite direction of the action, or thrust, from the engine (Thirdlaw).


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THE ROCK CYCLE

Magma and lava cool and solidify to form igneous rocks. Other rocks are brought to the Earths surface

through the uplifting of land when tectonic plates collide. Sediments are deposited in layers and over

time they cement together under pressure to form sedimentary rocks. When rocks are under extreme

heat or pressure, they

change into veryhard metamorphic

rocks. If too much

heat or pressure is

applied to rocks, they

melt and form

magma and the

whole cycle begins

again.

You will be shown the video The Rock Cycle, which will help you to answer the questions below.

IGNEOUS ROCKS

1. What does igneous mean?Born of Fire.

2. What do igneous rock formations look like?Jagged, craggy, with no discernible layers.

3. What do igneous rocks look like under magnification?Jigsaw-like, interlocking pattern of crystals.

4. How do igneous rocks form?They form when magma (molten rock) cools down and solidifies. The process involves CRYSTALLISATION.

5. What is granite?Magma that has cooled slowly beneath the earths surface, producing large crystals.

6. What is basalt?Magma (lava) that has cooled more quickly above the earths surface, producing small crystals.

7. Describe the materials found downstream in the river bed.Particles of a variety of sizes: sand pebbles boulders

Variety of rock types: sedimentary and igneous

Variety of shapes, but much more worn and rounded than formations upriver.


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SEDIMENTARY ROCKS

8. What do sedimentary rock formations look like?Distinct layers of rocks of different colour, texture, and hardness.

9. What is the process called by which rocks are worn down and carried along by wind or water?Erosion

10. What is sediment?Particles produced by erosion that are carried by wind/water/ice etc and DEPOSITED, usually at the bottom of a body of

water.

11. How do sediments become rocks? Give some examples.As sediment layers build up, older sediments are placed under pressure, which generates heat. This heat and pressure

hardens the sediments, which become cemented together by tiny clay-like particles, into rock

eg sand sandstone, mud mudstone(shale), lime limestone

METAMORPHIC ROCKS

12.

What do metamorphic rock formations look like?Often have a layered appearance (foliation), but unlike sedimentary rocks they are clearly composed of crystals.

13. How do metamorphic rocks form? Give some examples.By the action of heat and pressure underground on existing sedimentary or igneous rocks.

eg limestone marble, granite gneiss, mudstone(shale) slate

14. What can happen to metamorphic rocks if the temperature becomes very high?They can melt and return to the mantle of magma beneath the earths crust.

THE ROCK CYCLE

15. What causes the heating and squeezing that leads to these changes in the rocks in the earths crust?Movement of the plates of the earths crust, and the consequent collisions, friction, etc

In the space below complete the flow-chart that summarises how the three rock types are inter-converted over

time. Label each of the arrows to show what processes are involved in each change.

IGNEOUS ROCKS

METAMORPHIC SEDIMENTARY

SEDIMENTSMAGMA


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IDENTIFYING ROCKS

Q 1. How many different types of rock can you name?brainstorm

Q 2. List some rocks that are used for construction (buildings, garden walls, etc).Theyshould be able to suggest a few, eg bluestone, slate. Also an opportunity to discuss what rocks are and why bricks,

concrete etc are not classed as rocks.

EXPERIMENT 4: LOOKING AT ROCKS

Well take a closer look at some examples of the different types of rock.

1. Collect the five rock samples provided and a hand lens.

2. Describe the general appearance of each: What colour is it? Is it sparkly or dull? Is it smooth and consistent or is itmade up of little bits (& what do the little bits look like)? etc.

3. How hard is each rock? How easy is it to scratch each one with your fingernail?

4. Examine each carefully and record your observations in the table below.

Observations:

Rock Appearance H

1

sandstone

2

mudstone

3

basalt

4

marble

5

slate

Both sandstone (Rock 1) and mudstone (Rock 2) are examples ofsedimentary rocks. They are formed in

much the same way.

Q 3.In what way(s) are these two rocks different from basalt (Rock 3), marble (Rock 4) and slate (Rock 5)?

DDDoooeeesss aaa gggeeeooolllooogggiiisssttt

hhhaaavvveee rrroooccckkksss iiinnn hhhiiisss

hhheeeaaaddd???


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EXPERIMENT 5: A CLOSER LOOK AT SEDIMENTARY ROCKS.

1. Collec t a microsc op e and examine the slide s showing a

sc rap ing of Roc k 1 and Roc k 2. You should b e a b le to see tha t

sand stone is ma de up of tw o p arts.

2. Sketch and lab el a part of wha t you see a t the right:Emphasise the presence of larger grains amid many tiny clay particles.

3. Ca refully sc rap e a sma ll amo unt o f Roc k 2 into a test tub e a nd

shake it up with a little w ater. What d oes it loo k like?

Muddy water.

Q 1. Where might you find water like this?Muddy lakes, rivers etc.

SEDIMENTARY ROCKS

How are sedimentary rocks formed?

As we have seen, sedimentary rocks like sandstone consist of small bits (such as grains of sand) that have been

cemented together. How does this happen?

The process begins when existing rocks are worn down by wind and weather. The small pieces are washed or

blown along until they settle down as sediment. Gradually, further layers of sediment build up, compressing the

layers underneath.

Over long periods of time the pressure on these sediment layers causes them to harden into rock. Tiny clay

particles between the grains cement them together.

Label the oldest sediments and the youngest

sediments on the close-up of this diagram.

Rock1 Rock2

Teachers set of sedimentary rock slides(Demo )


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Types of sedimentary rock

Perhaps the most important difference between types of sedimentary rock is the size of the grains that make

them up.

Look at samples provide

sediment particles sedimentary rock formed

pebbles conglomerate

sand grains sandstone

tiny mud & clay

particlesmudstone/shale

From the size of the sediment particles in a sedimentary rock we can hypothesise about where and how the

sediment layers were originally deposited.

DEMONSTARION 1: DEPOSITION OF SEDIMENTS

You will be shown a jar containing water and a range of sediment

particles of different sizes. Record what happens after the jar is shaken

(complete the diagram) and then answer these questions:

Q 1. Which material deposited most quickly?coarse material (sand grains) - within a few seconds

Q 2. Which material deposited most slowly?fine material (mud/clay particles) - several minutes to hours until complete

Q 3. In rivers, streams, and shallow ocean regions the water moves quite quickly. What types of sedimentaryrocks would you expect to form from sediments deposited in these areas? Why?

Conglomerates and coarse-grained sandstones.Movement and turbulence in the water prevents the finer particles settling out.

Q 4. In large lakes and seas the water in the deeper areas moves slowly. What sedimentary rocks would youexpect to form from sediments deposited in these areas?

Mudstones.


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Folding of sedimentary rocks

Sediments deposited on the sea floor will naturally form horizontal layers of rock as the sediment hardens. These

layers are usually easy to see when the rocks become exposed on the surface.

Online activity available to demonstrate this.

Most materials will undergo plastic deformation when warm and brittle deformation when cold. If a force is

applied rapidly the material will break, but if force is applied slowly the material will deform plastically.

Q1. When rock layers are deformed plastically we call it a fold. Under what conditions do you think rocks

might be bent into a fold:

a. When they are hot or cold?b. When force is applied slowly or rapidly?

Q2. When rocks are broken it is called a fault. Under what conditions do you think a fault forms?

Q3. Look at these photographs. Which one shows a fault and which one a fold?

Q 4. Given that the layers of sedimentary rock visible in these photographs would originally have beenlaid down horizontally, what must have happened since?

The layers have been tilted and folded after their formation by changes in the earth's crust.

Folding and tilting of sedimentary rock layers has produced the important mountain chains on the earth. Thefolding process is accompanied by the most dramatic processes that occur at the earths surface: earthquakes and

volcanoes.

The eastern highlands of Australia were produced in this way. When their formation was completed (around 350

million years ago) this mountain chain stretched from the Cape York Peninsula to Tasmania, and was probably as

large as the largest present-day mountain chains (such as the Andes, which are about 6 km high).

Q 5. Today, the eastern highlands are relatively small compared to the worlds largest mountains. Whathas happened since their formation?

A long period of erosion has worn them down to roughly their present size.


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EXPERIMENT 6: INVESTIGATING WEATHERING

Aim: To observe the effect of 1. Heating and cooling on a sandstone rock, and 2. acids (chemical) on limestone

rocks.

Results:

Observation of heating the sandstone:

State whether there is a fast, a slow, or no reaction of the limestone.

QUESTIONS:

1. What causes the following types weathering?

a. Physical

b. Chemical

Test Tube Rate of ReactionA hydrochloric Acid

B Soda water

C Vinegar

D Water

Method:

1. Hold a small piece of a sandstone rock with a metal tongs, and heat it in the blue flame of the Bunsenburner for about 30 seconds.

2. Then dip the hot rock in a beaker of tap water. Repeat this process of heating and cooling at least three

times.

3. Place a filter paper in a funnel and filter the water containing fragments of rocks. Remove the filter paper,

allow it to dry and examine the fragments of rock using a magnifying glass.

4. Label 4 test tubes A to D and place them in a test tube stand. Place 4 pieces of limestone of similar size into

these test tubes.

5. Pour 5 mL hydrochloric acid into test tube A. Pour 5 mL of soda water into test tube B. Pour 5 mL vinegar

into test tube C. Pour 5 mL tap water into test tube D.

6. Leave the limestone rocks for at least 10 minutes in the test tubes and observe the reaction. Record yourresults in the table.


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IGNEOUS ROCKS(There are samples for the class to look at.)How do igneous rocks form?

Igneous rocks form whenmagma, the mixture of molten minerals beneath the earths crust, cools down. When

this happens the different minerals form crystals, and these crystals pack together as the rock solidifies.

The type of igneous rock that forms depends on how long the magma takes to cool down and crystallise.

Note: stick to these examples for simplicity.

The diagram below shows four different ways that magma can cool down and solidify.

Q 6. What type of igneous rock you might expect to find at each site. Look at each sample and explain yourchoice.

1 Basalts, as the lava will cool moderately quickly in air, producing small crystals.2 Granites, as the magma, being blanketed by the surrounding rock, will cool slowly, resulting in large crystals.3 Fine basalts or obsidian, as the water will cool the magma very quickly, resulting in very small or no crystals.4 Pumice, formed from rapidly cooled magma, trapping gases during an explosive volcanic eruption.

MAGMAtime of cooling

no crystalseg obsidian

small crystalseg basalt

large crystalseg granite

rappe ases

egpumice

magma

molten magma or lava

solidified igneous rock

1

2

3

4


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DEMONSTRATION 2: JELLY VOLCANO

PURPOSE: To understand how magma moves inside volcanoes to create channels and chambers such as dykes

and sills and to see how these channels can influence a volcanic eruption.

METHOD:

EXPERIMENT 7: A CLOSER LOOK AT IGNEOUS ROCKS

1. Collec t a microscop e a nd e xamine the slide of b asalt showing a

sec tion of Roc k 3. You should b e a b le to see a num ber of differentcoloured c rysta ls. The c olours ma y be c learer with a d im ligh t. Sketc h a

pa rt of what you see in the spa ce a t the right.

2. Using the Key be low, try to lab el a few of the c rysta ls you ha ve d raw n.

mineral descriptionfeldspar colourless crystals

augite pale green crystals (hard to see)

olivine rounded crystals with brown edges

magnetite small, black crystals

Many Melbourne suburbs sit on basalt, and it has been a commonly used building material.

Q 7. What is basalt like this better known as?Bluestone

Q 8. List some examples of the use of this material that you are familiar with.eg garden edges, old buildings (esp churches)

Q 9. What causes the sparkly appearance of basalt?Reflection from the small crystals that make it up.

1. Set up the 2 bricks on the safety mat and place pegboard on top.

2. Turn jelly out on top of the pegboard between the two bricks with the collecting tray underneath.

3. Using red food dye, prepare coloured water (magma).

4. Predict what will happen when the red water is injected into the jelly volcano. What shape will it take? What

direction will it go in? Will the magma move outwards and upwards? What influences this?

5. Fill the syringe with the coloured water. Remove any air bubbles. (Air tends to fracture the jelly).

6. Place the end of the syringe up through one of the holes in the pegboard and gently inject the magma into the

jelly.

7. Refill the syringe and repeat the same process in several other positions along the pegboard. Compare the

magma migration each time. Are there differences in the direction the magma moves during injections in the

central part of the jelly volcano compared to injections near the edges?

8. Use a sharp knife to cut the jelly volcano in half. Examine the cut surface. Note the traces made by the red

magma; these are similar to what we see in highway road cuts.

Teachers set of Igneous Rock Slides with notes


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EXPERIMENT 8: A CLOSER LOOK AT METAMORPHIC ROCKS

Rocks in the earth's crust are subjected to considerable heat and pressure. These can cause a rearrangement of the

crystals or grains in the rock to produce a new, harder type of rock called a metamorphic rock.

Q 10. What causes pressure within the earth's crust?Successive rock layers stack up over time and compress the layers underneath..Q 11. This pressure can itself generate a lot of heat. What is another source of

heat in the earth's crust?

Magma. Rocks in the vicinity of magma are likely candidates for metamorphosis.

Look at the slide provided of the metamorphic rock, gneiss, and sketch a part of what

you see in the space provided.

Both sedimentary and igneous rocks are changed into metamorphic rocks. The type of

rock that forms depends on the 'parent' rock from which it formed.

Here are some examples:

The rock ... is transformed into the metamorphic rock ...

mudstone (shale) slate

granite gneiss

limestone marble

GEOLOGICAL HISTORIES

Examinetheprofileshownintheblockdiagrambelowandthenanswerthefollowingquestions.

Dyke of igneous rockSill of igneous rock

Recent lava flow

buried lava flow

mudstone

sandstone

basalt

injected igneous rocA

B

C

D

E

F

G

H

I

J

K

Teachers set of Metamorphic Rock

Slides with notes


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Q 1. Which rocks (A-K) are sedimentary rocks?A, B, C, D, E, F, H

Q 2. Which rocks are igneous rocks?G, I, J

Q 3. Which rock is the oldest? What type of rock is it?H. Sandstone (sedimentary).

Q 4. Describe how rocks A-F would have formed. What does the alternation of layers suggest?By deposition of sediments at the bottom of a sea or lake, followed by hardening of the sediment layers as the result of

pressure and heat over time.The different layers suggest that the depth of water in which the sediments were laid down changed several times

throughout this period. The mudstone sediments would have been laid down when the water was deeper and less turbulent.

Q 5. How do you think that the age of these rocks might be determined?By examination of the fossils found in the sedimentary rocks (not the igneous rocks!). Fossils of known species can often be

matched with similar fossils at other sites around the world.

Other techniques, such as carbon-dating, can provide additional evidence of age.

Q 6. How did rock G form?Probably lava flow from an ancient volcano.

Q 7. When this happened, which of the other rocks had already formed?Only rock H was present at the time.

Q 8. Which rock has formed most recently?K, as the result of a recent lava flow.

Q 9. Rocks I andJ both formed as magma from below was squeezed into the existing rock. From thediagram, what is the difference between a "dyke" and a "sill"?

A dyke forms when magma is injected into a fissure or fault that runs through existing rock layers.

A sill forms when magma is injected into the space between two existing rock layers, forming a layer of igneous rock

parallel with existing layers.


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Q 10. Why does rock I protrude above the ground?Rocks A and I are both exposed to the forces of erosion. Rock I is igneous and harder than Rock A, so it erodes more slowly.

ie Rock A has eroded relatively quickly, leaving dyke of Rock I protruding.

Q. What is the evidence for our knowledge of the age of rocks and what can we learn from rocks?

There are a number of activities you may wish to do with your class.

1. Examine the local area of Melbourne and the history of volcanic activity.

2. Dating Fossils (found on Learning Point)

3. Activity on Classifying Rocks (found on Learning Point)

Science to GCSE

Section 4.32: Sun, Earth, Moon and sky. pg 196

Section 4.33: Planets, stars, and galaxies. Pg 198

Section 4.35: Birth and death. Pg 203

Section 4.26: Plates and seismic waves. Pg 184

Section 3.30: Changes in rocks. Pg 132

earth+ +student+notes+10

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