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Term pack

Year 8 Science

Name: ________________________

Skills in this pack

  • Life processes in animals
  • Adolescence: growth and change
  • Life processes in plants
  • Acidic, basic and neutral substances
  • Physical and chemical changes
  • Metals and non-metals
  • Heat transfer in nature
  • Measuring time
  • Speed and motion
  • Light, shadows and reflection
  • Circuits and their components
  • The Earth, the Moon and the Sun

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Year 8 Science · 1 of 12

Life processes in animals

Follow food through the alimentary canal and say what each part does, tell breathing from respiration, and match an animal to the way it takes in oxygen.

Before you start

The parts of the human respiratory system, from the nostrils down.

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  1. 1. Nostrils
  2. 2. Windpipe
  3. 3. Lung
  4. 4. Rib cage
  5. 5. Diaphragm

Air comes in at the nostrils, down the windpipe, and into branches that end in tiny balloon-like sacs called alveoli inside the lungs. The rib cage guards the lungs; the dome-shaped diaphragm below them does the pulling.

  1. 1.Why is the inner lining of the small intestine covered in thousands of finger-like projections?

    • a) They make the digestive juices the small intestine needs
    • b) They increase the surface area, so nutrients are absorbed efficiently
    • c) They stop acid from the stomach reaching the intestine wall
    • d) They grip the food and stop it moving on too fast

  2. 2.Tap the part of this alimentary canal where most of the digested nutrients are absorbed into the blood.

    Write the number of the part.

    12345

  3. 3.Put the parts of the alimentary canal in the order food passes through them, starting at the mouth.

    • Stomach
    • Small intestine
    • Large intestine
    • Rectum
    • Mouth
    • Anus
    • Oesophagus

  4. 4.Sort each animal by the part of its body that takes in oxygen.

    Groups: Breathes with lungs · Breathes with gills · Breathes through moist skin

    • Tadpole
    • Earthworm
    • Fish
    • Lion
    • Snake

  5. 5.Respiration uses oxygen to break down glucose. What comes out of it?

    • a) Oxygen, water and starch
    • b) Glucose and energy, with nothing given off
    • c) Carbon dioxide, water and energy
    • d) Carbon dioxide and starch

  6. 6.The large intestine is shorter than the small intestine. Why is it called large?

    • a) It was discovered before the small intestine was
    • b) It holds more food at one time than the stomach
    • c) It does more of the digesting than any other part
    • d) It is wider than the small intestine

  7. 7.A frog begins life as a tadpole in water and grows into an adult that spends time on land. How does its breathing change?

    • a) The tadpole uses gills; the adult uses lungs on land and its skin in water
    • b) It uses gills throughout, in water and on land alike
    • c) The tadpole uses lungs; the adult uses gills
    • d) It uses its skin throughout, and the lungs do nothing

  8. 8.A cow brings partially digested grass back up to its mouth and chews it thoroughly. What is that process called?

Life processes in animals · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 2 of 12

Adolescence: growth and change

Place adolescence among the stages of life, name the changes it brings and what drives them, and say what looks after health at this age.

Before you start

Slide along this line of ages and see where the chapter puts adolescence.

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Adolescence generally begins around 10 and usually runs to 19. Before about 10 to 12, most of what changes in a body is height and weight; the rest begins after that. These are the chapter's general ages, not a timetable anyone has to keep to.

  1. 1.The bump that may appear at the front of the throat as the voice box grows has a name in this chapter. What is it?

  2. 2.What does the chapter give as the cause of acne?

    • a) Dust settling on skin that is not washed often enough
    • b) More oily secretions from the skin, which clog its pores and let infection in
    • c) Eating foods that are rich in fat
    • d) The skin stretching as a person grows taller

  3. 3.The chapter gives an age around which adolescence generally begins. Which age is it?

    Mark the line with an X.

    012345678910111213141516171819202122232425

  4. 4.Why does an adolescent boy's voice often sound hoarse for a while?

    • a) He is speaking more loudly than he used to
    • b) His lungs have grown faster than his throat
    • c) His throat is short of water
    • d) His voice box is growing

  5. 5.What is the name for the stage in which a child's body changes, inside and out, into an adult body capable of reproduction?

  6. 6.Match each nutrient to what the chapter says it does for a growing body.

    • Calcium
    • Proteins
    • Iron
    • helps bones grow well
    • help growth, strength and energy
    • helps blood to form

  7. 7.Chemicals made in the body drive most of the changes of adolescence and are released on signals from the brain. What are they called?

  8. 8.What makes a change a secondary sexual characteristic?

    • a) It happens after the age of 19
    • b) It can be seen from outside the body
    • c) It helps tell males from females but takes no direct part in reproduction
    • d) It happens to boys and not to girls

Adolescence: growth and change · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 3 of 12

Life processes in plants

Say what photosynthesis needs and what it gives back, read the experiment that proves each ingredient, and name the tubes that carry water up and food out.

Before you start

The parts of a plant, and what each one does with water and with food.

123
  1. 1. Leaf
  2. 2. Stem
  3. 3. Roots

The leaf is where the food is made. Water and minerals go up from the roots through tubes called xylem, inside the stem. Food made in the leaves goes out through a second set of tubes called phloem, to wherever the plant needs it or stores it. Tiny pores in the leaf surface, the stomata, let gases in and out.

  1. 1.A leaf with green and non-green patches is taken from a plant that has been standing in sunlight. Iodine is applied. What happens?

    • a) The non-green patches go blue-black and the green ones do not
    • b) Nothing changes colour, because the leaf is still alive
    • c) The whole leaf goes blue-black, green patches and pale ones alike
    • d) The green patches go blue-black and the non-green ones do not

  2. 2.Sort each substance by the part it plays in photosynthesis.

    Groups: Taken in by photosynthesis · Given out by photosynthesis

    • Oxygen
    • Water
    • Glucose
    • Carbon dioxide

  3. 3.Put the steps of the starch test on a leaf in order, starting from softening the leaf in boiling water.

    • Decolourise it in alcohol standing in a beaker of boiling water
    • Lay the pale leaf out on a plate
    • Soften the leaf in boiling water
    • Put a few drops of dilute iodine solution on it
    • A blue-black colour means starch is present

  4. 4.Three identical saplings are grown for two weeks: A in sunlight with water, B in sunlight without water, C in the dark with water. What do their fates show?

    • a) A plant needs both sunlight and water to grow
    • b) A plant needs water and can manage without sunlight
    • c) Neither sunlight nor water makes much difference over two weeks
    • d) A plant needs sunlight and can manage without water

  5. 5.Which pair of ingredients does a plant draw from its surroundings to make food?

    • a) Starch from the soil and sunlight from the sky
    • b) Carbon dioxide from the air and water from the soil
    • c) Carbon dioxide from the soil and oxygen from the air
    • d) Oxygen from the air and glucose from the soil

  6. 6.The food a plant makes is first produced as a simple carbohydrate, which the plant later turns into starch for storage. What is that simple carbohydrate?

  7. 7.What is the name of the process by which a plant prepares its food in the presence of sunlight and chlorophyll?

  8. 8.Why does the chapter call leaves the food factories of a plant?

    • a) They take in the water and minerals the plant lives on
    • b) They store most of the plant's food until it is needed
    • c) They are the part of the plant that animals eat most often
    • d) They are the primary site of photosynthesis, where the food is made

Life processes in plants · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 4 of 12

Acidic, basic and neutral substances

Sort everyday substances as acidic, basic or neutral, read what each natural indicator is telling you, and use neutralisation to explain an ant bite and a sour field.

  1. 1.Which of these did the litmus tests find to be basic?

    • a) Amla juice
    • b) Vinegar
    • c) Sugar solution
    • d) Baking soda solution

  2. 2.Red rose extract has been added to each of these three test tubes. Tap the tube holding a basic solution.

    Write the number of the part.

    123

  3. 3.Manya is blindfolded and handed two solutions to tell apart. Which kind of indicator could she still use?

    • a) Red rose extract, because it is a strong colour
    • b) Litmus paper, because the strips feel different
    • c) An olfactory indicator, whose smell changes
    • d) Turmeric paper, because turmeric is a familiar spice

  4. 4.Litmus is not made in a laboratory — it is taken from a living thing that grows on rocks and tree bark. What kind of organism is it obtained from?

  5. 5.A drop of an unknown liquid is put on turmeric paper and the yellow does not change. Which two possibilities are still open?

    • a) Nothing is open — turmeric paper settles it
    • b) It is acidic, or it is neutral
    • c) It is acidic, or it is basic
    • d) It is basic, or it is neutral

  6. 6.A substance that shows one colour in an acid and a different colour in a base has a two-word name in this chapter. What is it?

  7. 7.A basic solution is dropped onto each of these three indicators. Match each one to what it does.

    • Red litmus paper
    • Red rose extract
    • Turmeric paper
    • turns blue
    • turns green
    • turns red

  8. 8.Each of these was tested with blue and red litmus paper. Sort them by the nature the papers reported.

    Groups: Acidic · Basic · Neutral

    • Soap solution
    • Tamarind water
    • Lemon juice
    • Sugar solution
    • Washing powder solution
    • Vinegar
    • Salt solution
    • Lime water

Acidic, basic and neutral substances · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 5 of 12

Physical and chemical changes

Decide whether a change has made a new substance or merely rearranged an old one, say what combustion needs, and name the slow changes that turn rock into soil.

Before you start

Look closely at a burning candle. Two different kinds of change are going on at once.

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  1. 1. The flame
  2. 2. The wick
  3. 3. The pool of melted wax
  4. 4. The solid wax of the candle

The wax melting into a pool, being drawn up the wick and turning to vapour are physical changes — it is still wax. Inside the flame, that vapour burns and becomes something else. That part is a chemical change.

  1. 1.Which statement describes a physical change?

    • a) The state of a substance may change, and no new substance is formed
    • b) A substance with different properties is formed
    • c) A chemical reaction takes place and gives out heat
    • d) The change is impossible to reverse

  2. 2.Combustion needs three things at the same time. Which set is right?

    • a) A fuel, carbon dioxide, and sunlight
    • b) A fuel, water, and a flame
    • c) Oxygen, heat, and a container to hold the fire in
    • d) A fuel, oxygen, and heat enough to reach the ignition temperature

  3. 3.Sand that a river carried settles on the riverbed, and over thousands of years it becomes rock. What does the chapter say about undoing changes like that?

    • a) They can be reversed, but just in a laboratory
    • b) They can be reversed by grinding the rock back to sand
    • c) They reverse themselves each rainy season
    • d) They cannot be reversed

  4. 4.Rock, pebbles and soil are picked up by wind or flowing water and carried somewhere else. What is that process called?

  5. 5.A black basalt rock exposed to damp air for a long time grows a red layer on its surface. What kind of change is that?

    • a) A chemical change — iron in the rock has turned into iron oxide
    • b) A physical change — the surface has been worn smooth by rain
    • c) Neither — the rock was red underneath a black coating from the start
    • d) A physical change — the red is dust that has settled and stuck

  6. 6.Sort each change by whether a new substance was formed.

    Groups: Physical change · Chemical change

    • Folding paper into a shape
    • Adding baking soda to vinegar
    • Burning a magnesium ribbon
    • Cooking food
    • Rusting of an iron nail
    • Melting an ice cube
    • Crushing chalk into powder

  7. 7.A candle burns. Which kinds of change are going on?

    • a) Neither, because the candle is just getting shorter
    • b) Chemical alone, because a flame is a chemical reaction
    • c) Both — the wax melting and evaporating are physical, and the vapour burning is chemical
    • d) Physical alone, because the wax is still wax the whole way through

  8. 8.Someone's clothes catch fire and a woollen blanket is wrapped around them. Why does that put the fire out?

    • a) It soaks up the fuel that is feeding the flames
    • b) It cools the clothes below their ignition temperature at once
    • c) It cuts off the supply of air, so the burning has no oxygen
    • d) It reflects the heat back onto the fire and smothers it with light

Physical and chemical changes · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 6 of 12

Metals and non-metals

Tell metals from non-metals by malleability, ductility, sonority and conduction, say what rusting and corrosion need, and give the nature of a metal oxide and a non-metal oxide.

  1. 1.Match each non-metal to the everyday job the chapter gives it.

    • Nitrogen
    • Chlorine
    • Iodine
    • goes into making fertilisers
    • put on a wound as an antiseptic
    • used to purify water

  2. 2.Why does the chapter say that wood, glass and plastic are neither metals nor non-metals?

    • a) Because they are made in factories rather than dug out of the ground
    • b) Because they float in water, and metals and non-metals sink
    • c) Because those two names are for elements, and these materials are not elements
    • d) Because they are neither hard nor soft enough to be tested

  3. 3.Heat passing from one point of a spoon along to another point has a one-word name in this chapter. What is it?

  4. 4.What has to reach an iron nail before a brown deposit forms on it?

    • a) Sunlight and dry air
    • b) Water on its own
    • c) Water and air together
    • d) Dry air on its own

  5. 5.Match each property to what a material showing it can do.

    • Malleability
    • Ductility
    • Sonority
    • gives a ringing sound when struck
    • can be drawn into wires
    • can be beaten into thin sheets

  6. 6.An iron gate left out through a wet season grows a brown flaky deposit. What is that deposit called?

  7. 7.A gas made by burning a non-metal is dissolved in water. What nature would you expect that solution to have?

    • a) Neutral
    • b) Acidic
    • c) Basic first and then acidic
    • d) Basic

  8. 8.Sort each of these elements into its family.

    Groups: Metal · Non-metal

    • Iron
    • Magnesium
    • Copper
    • Nitrogen
    • Aluminium
    • Carbon
    • Oxygen
    • Sulfur

Metals and non-metals · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 7 of 12

Heat transfer in nature

Tell conduction, convection and radiation apart by what the particles do, explain land and sea breezes, and follow water from the sea to an aquifer.

Before you start

Four pins are stuck along a metal strip with wax, and one end of the strip is heated. Here is the strip, pin by pin.

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  1. 1. Pin I
  2. 2. Pin II
  3. 3. Pin III
  4. 4. Pin IV

The heat travels along the strip from the heated end towards the cold one, melting each blob of wax as it arrives. Pin I sits nearest the flame and Pin IV farthest away, so the pins drop one after another in that order. The strip itself has not moved anywhere — just the heat has.

  1. 1.Groundwater levels in many towns are falling. Which pair of causes does the chapter give?

    • a) Too much rainwater harvesting, and too many recharge pits
    • b) Aquifers turning to solid rock, and wells being dug too shallow
    • c) Heavy extraction for a growing population, and concrete surfaces that leave less room for water to soak in
    • d) Rainfall stopping altogether, and rivers changing course

  2. 2.Match each way of transferring heat to what the particles are doing.

    • Conduction
    • Convection
    • Radiation
    • heat crosses with no medium to carry it
    • heat passes along, and the particles stay where they are
    • the heated particles themselves move, carrying the heat

  3. 3.Which of the three ways of transferring heat can cross a space with nothing in it?

    • a) Radiation
    • b) Conduction
    • c) Conduction and convection both
    • d) Convection

  4. 4.Why is light-coloured clothing more comfortable in summer?

    • a) It lets sweat evaporate faster than dark cloth does
    • b) It conducts heat away from the body faster than dark cloth
    • c) It is made of thinner cloth than dark clothing is
    • d) It reflects most of the heat falling on it, while dark surfaces absorb more

  5. 5.The same amount of water is poured through one bottle of clay, one of sand and one of gravel. Through which does it come out fastest, and why?

    • a) Sand, because it is the driest of the three
    • b) They finish together, because the same water was poured into each
    • c) Gravel, because the spaces between its particles are the widest
    • d) Clay, because its particles are the smallest and pack loosely

  6. 6.Sort each material by how readily it lets heat pass through.

    Groups: Good conductor of heat · Poor conductor of heat

    • Glass
    • Steel
    • Wood
    • Clay
    • Air
    • Aluminium

  7. 7.The seeping of surface water down through soil and rock has a one-word name in this chapter. What is it?

  8. 8.An underground layer of sediment and rock that holds water in its pore spaces, and that a bore well is drilled into, has a name. What is it?

Heat transfer in nature · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 8 of 12

Measuring time

Say how old clocks kept time, find a pendulum's time period from a count of oscillations, and convert between the second, the minute and the hour.

Before you start

The parts of a simple pendulum, and where the bob reaches at one extreme.

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  1. 1. The support
  2. 2. The thread
  3. 3. The bob
  4. 4. One extreme

The dark bob hangs at the mean position, straight below the support. The pale one shows where it reaches at one extreme; there is a matching extreme on the other side. One oscillation is mean, extreme, across to the other extreme, back to mean.

  1. 1.What does a quartz clock count to keep time?

    • a) Drops of water falling through a fine hole
    • b) The turning of gears driven by a hanging weight
    • c) The swings of a very short pendulum
    • d) Very rapid vibrations of a quartz crystal

  2. 2.Which of these is written correctly, following the chapter's rules for units of time?

    • a) 30sec
    • b) 30 s
    • c) 30 Sec
    • d) 30S

  3. 3.A song lasts 4 minutes. How many seconds is that? Answer with a number.

  4. 4.A journey takes 6 hours. How many minutes is that? Answer with a number.

  5. 5.The bowl of a Ghatika-yantra was holed so that it took 24 minutes to fill and sink. Into how many of those intervals was a day divided?

    • a) 24
    • b) 60
    • c) 100
    • d) 12

  6. 6.A pendulum takes 20 seconds to complete 10 oscillations. What is its time period, in seconds? Answer with a number.

  7. 7.The time a pendulum takes to complete one oscillation has a two-word name. What is it?

  8. 8.What is the SI unit of time? Give the word, not the symbol.

Measuring time · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 9 of 12

Speed and motion

Work out speed, distance or time from the other two, choose between m/s and km/h, and tell uniform linear motion from non-uniform.

Before you start

A train leaves station A and reaches station D. Its position along the straight track is marked out below.

0120

Read the marks as the position of a train at equal intervals of time. When each gap between successive positions matches the one before, the speed is not changing and the motion is uniform. When the gaps grow or shrink, the speed is changing and the motion is non-uniform.

  1. 1.A car's journey is 60 kilometres and it takes 1 hour, so its speed works out at 60 kilometres per hour. But it stopped twice at signals. What does the chapter call the 60?

    • a) Its lowest speed
    • b) Its uniform speed
    • c) Its average speed
    • d) Its highest speed

  2. 2.Match each instrument on a vehicle's dashboard to what it tells the driver.

    • Speedometer
    • Odometer
    • shows how fast the vehicle is going right now
    • shows how far the vehicle has travelled altogether

  3. 3.Sort each stretch of a train's journey along a straight track.

    Groups: Uniform linear motion · Non-uniform linear motion

    • A train pulling out of a station and picking up speed
    • A train covering different distances in successive ten-minute intervals
    • A train slowing down as it comes into a station
    • A train running at an unchanging speed along a straight stretch
    • A train covering the same distance in each ten-minute interval

  4. 4.A cyclist covers 240 metres in 30 seconds. What is the cyclist's speed in metres per second? Answer with a number.

  5. 5.A train is moving at 72 kilometres per hour. What is that speed in metres per second? Answer with a number.

  6. 6.The chapter calls uniform linear motion an idealisation. Why?

    • a) Objects are seldom found holding a constant speed for long, which is why average speeds are used
    • b) It applies to trains but to nothing else
    • c) Speed cannot be measured accurately enough to check it
    • d) Straight tracks do not exist in practice

  7. 7.A train travels at a speed of 90 kilometres per hour. How many hours does it take to cover 360 kilometres? Answer with a number.

  8. 8.Three sprinters are part-way through a race on a straight track and one of them is ahead of the others. What does that tell you?

    • a) She started before the others did
    • b) She has a longer stride, which is a different thing from speed
    • c) She has covered more distance in the same time, so she is the faster
    • d) Nothing until the race is over

Speed and motion · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 10 of 12

Light, shadows and reflection

Tell luminous objects from non-luminous, use the straight-line rule to explain shadows, and give the four properties of an image in a plane mirror.

Before you start

A torch, an opaque object and a screen — the three parts of a shadow set-up.

1234
  1. 1. Torch
  2. 2. Object
  3. 3. Screen
  4. 4. Shadow

Take away any one of the three and there is nothing to see: no light, no object to block it, or no surface for the dark patch to land on. In everyday life a wall, a floor or the ground plays the part of the screen.

  1. 1.A red ball and a blue ball of the same shape are held in the same place in front of a torch. What can you say about their shadows?

    • a) The red ball casts the darker shadow, because red is the deeper colour
    • b) One shadow is reddish and the other bluish
    • c) Both shadows are the same, because changing an object's colour does not change its shadow's colour
    • d) The blue ball casts no shadow, because blue lets light through

  2. 2.A candle flame shines through a pinhole in a card onto a screen behind it. What does the image look like?

    • a) Too faint to have a shape
    • b) Upside down
    • c) Left and right swapped, but the right way up
    • d) The right way up

  3. 3.Why does a kaleidoscope show so many different patterns?

    • a) Its three mirrors reflect each other's reflections, and turning it rearranges the pieces
    • b) The tracing paper at the end scatters the light into new colours
    • c) The coloured pieces inside change colour as the tube warms
    • d) Its single mirror flips the pattern each time it is turned

  4. 4.What three things do you need in order to see a shadow?

    • a) A source of light, an opaque object, and a screen
    • b) A source of light, a transparent object, and a mirror
    • c) A mirror, an opaque object, and a screen
    • d) Sunlight, a coloured object, and a dark room

  5. 5.A shiny plate held in sunlight throws a bright patch onto a shaded wall, because it has changed the direction the light was travelling in. What is that change of direction called?

  6. 6.Match each item to what it does.

    • A pinhole camera
    • An opaque object
    • A transparent object
    • A shadow
    • blocks light completely
    • lets light pass almost completely through
    • forms an inverted image
    • the dark region formed behind an object

  7. 7.A pen stands in front of a plane mirror, drawn here as the tall bar in the middle. The image is the one drawn with a broken outline. Tap the image of the pen.

    Write the number of the part.

    123

  8. 8.Why is the word AMBULANCE painted reversed across the front of an ambulance?

    • a) So that it can be read from a great distance
    • b) So that it stays readable when the ambulance is moving fast
    • c) So that it reads the right way round in the rear-view mirror of the vehicle ahead
    • d) So that it looks different from ordinary vehicle lettering

Light, shadows and reflection · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 11 of 12

Circuits and their components

Name the parts of a torch circuit and what each does, read a circuit diagram's symbols, tell a conductor from an insulator, and say when a lamp glows and when it does not.

Before you start

Take apart an incandescent torch lamp and look at what makes the light.

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  1. 1. Glass bulb
  2. 2. Filament
  3. 3. Metal case
  4. 4. Metal tip

The filament is the thin wire that gets hot and glows. The metal case and the metal tip are the lamp's two terminals, kept apart so they cannot touch. An LED lamp has no filament inside it — it makes light a different way.

  1. 1.A torch is slid to OFF. What is true of its circuit while it sits like that?

    • a) It is closed, but the current is too weak to light the lamp
    • b) It is open, and the current takes a shorter path instead
    • c) It is open — a gap is left that the current cannot cross
    • d) It is closed, and the current is stored inside the cell

  2. 2.In the symbol for an electric cell, one line is drawn long and one short. What does the long line stand for?

    • a) The wire leaving the cell
    • b) The amount of energy left in the cell
    • c) The negative terminal
    • d) The positive terminal

  3. 3.An incandescent lamp is taken out of a circuit and put back with its two terminals the other way round. What happens?

    • a) It glows just as before, because the circuit is still complete
    • b) It glows dimly, because half the current is turned back
    • c) It glows more brightly, because the current now runs the natural way
    • d) It stays dark, because current can pass through it in one direction

  4. 4.This is the circuit diagram of a torch. Tap the symbol for the switch.

    Write the number of the part.

    123

  5. 5.Each of these was held across the two free ends of a tester's wires. Sort them by whether the lamp glowed.

    Groups: Conductor · Insulator

    • Rubber eraser
    • Metal key
    • Plastic scale
    • Aluminium foil
    • Wooden stick
    • Copper wire

  6. 6.Silver, copper and gold are the three best conductors. Why is the metal inside an electric wire usually copper?

    • a) Copper is the one metal that conducts electricity
    • b) Copper costs less and there is plenty of it, and it conducts nearly as well
    • c) Copper is easier to draw into a thin wire than any other metal
    • d) Silver and gold are insulators

  7. 7.Follow the current round a working torch circuit, starting at the positive terminal of the cell.

    • The positive terminal of the cell
    • The filament of the lamp
    • The switch, closed to ON
    • The negative terminal of the cell

  8. 8.Why are the plug tops, switch covers and wire coverings in a house made of rubber, plastic or ceramic?

    • a) They are cheaper to make than the metal parts underneath
    • b) They are conductors, so they carry the current away from a person
    • c) They stop the metal underneath from rusting
    • d) They are insulators, so they keep the current from reaching a person

Circuits and their components · Year 8 Science · www.arenapublications.com/learn

Year 8 Science · 12 of 12

The Earth, the Moon and the Sun

Tell rotation from revolution, explain day, night and the seasons from the Earth's turning and its tilt, and say what lines up during each kind of eclipse.

Before you start

The Sun, the Moon and the Earth, lined up for a solar eclipse.

123
  1. 1. The Sun
  2. 2. The Moon
  3. 3. The Earth

The Moon sits between the Sun and the Earth and throws a small shadow onto the Earth's surface. Stand inside that shadow and the Sun is hidden — a total solar eclipse. Stand where the Moon covers part of the Sun and you see a partial one.

  1. 1.How does watching a lunar eclipse differ from watching a solar one?

    • a) A lunar eclipse also needs eye protection, of a different kind
    • b) An eclipsed full Moon can be watched safely with the naked eye
    • c) A lunar eclipse lasts a few seconds, so there is no time to look
    • d) A lunar eclipse can be watched safely through binoculars but not directly

  2. 2.Why does the Northern Hemisphere have summer in June?

    • a) It is tilted towards the Sun, so the sunlight is more intense and lasts more than 12 hours a day
    • b) It is passing through the part of the orbit nearest the Sun
    • c) The Earth rotates more slowly in June, giving longer days
    • d) The Sun gives out more heat during those months

  3. 3.The day-night cycle goes round and round with no true beginning, so start from the step where your place turns into the sunlight, and the Sun rises, and put the rest in order.

    • Your place is on the half facing the Sun — daytime
    • Your place turns into the sunlight, and the Sun rises
    • Your place turns out of the sunlight, and the Sun sets
    • Your place is on the half turned away from the Sun — night

  4. 4.What causes the seasons on the Earth?

    • a) The hemisphere tilted towards the Sun being closer to it
    • b) The tilt of the Earth's axis, together with the Earth's spherical shape
    • c) The Earth rotating faster in some months than in others
    • d) The Earth being at different distances from the Sun over the year

  5. 5.Here are the Sun, the Earth and the Moon during a lunar eclipse. Tap the body whose shadow is falling on the Moon.

    Write the number of the part.

    123

  6. 6.Seen from above the North Pole, which way does the Earth rotate?

    • a) Anti-clockwise, which is from East to West
    • b) Clockwise, which is from West to East
    • c) Anti-clockwise, which is from West to East
    • d) Clockwise, which is from East to West

  7. 7.Why do the southern states of India feel the change of seasons less strongly than places further north?

    • a) They lie close to the equator, where daylight and sunlight intensity vary little through the year
    • b) Their days run shorter than 12 hours the year round
    • c) They are closer to the Sun, so they stay warm the year round
    • d) The Earth's tilt does not affect the Southern Hemisphere

  8. 8.Match each kind of eclipse to what is happening.

    • Solar eclipse
    • Lunar eclipse
    • A Moon completely inside the Earth's shadow
    • the Earth comes between the Sun and the Moon
    • a total lunar eclipse, with the Moon turned dark red
    • the Moon comes between the Sun and the Earth

The Earth, the Moon and the Sun · Year 8 Science · www.arenapublications.com/learn

Answer keys — Year 8 Science

In the same order as the worksheets.

Life processes in animals

  1. 1. b) They increase the surface area, so nutrients are absorbed efficiently
  2. 2. 4 — Small intestine
  3. 3. 1. Mouth 2. Oesophagus 3. Stomach 4. Small intestine 5. Large intestine 6. Rectum 7. Anus
  4. 4. Lion → Breathes with lungs; Snake → Breathes with lungs; Fish → Breathes with gills; Tadpole → Breathes with gills; Earthworm → Breathes through moist skin
  5. 5. c) Carbon dioxide, water and energy
  6. 6. d) It is wider than the small intestine
  7. 7. a) The tadpole uses gills; the adult uses lungs on land and its skin in water
  8. 8. rumination

Adolescence: growth and change

  1. 1.
    • adam's apple
    • the adam's apple
    • adams apple
  2. 2. b) More oily secretions from the skin, which clog its pores and let infection in
  3. 3. 10
  4. 4. d) His voice box is growing
  5. 5. puberty
  6. 6. Calcium → helps bones grow well; Proteins → help growth, strength and energy; Iron → helps blood to form
  7. 7.
    • hormones
    • hormone
  8. 8. c) It helps tell males from females but takes no direct part in reproduction

Life processes in plants

  1. 1. d) The green patches go blue-black and the non-green ones do not
  2. 2. Carbon dioxide → Taken in by photosynthesis; Water → Taken in by photosynthesis; Glucose → Given out by photosynthesis; Oxygen → Given out by photosynthesis
  3. 3. 1. Soften the leaf in boiling water 2. Decolourise it in alcohol standing in a beaker of boiling water 3. Lay the pale leaf out on a plate 4. Put a few drops of dilute iodine solution on it 5. A blue-black colour means starch is present
  4. 4. a) A plant needs both sunlight and water to grow
  5. 5. b) Carbon dioxide from the air and water from the soil
  6. 6. glucose
  7. 7. photosynthesis
  8. 8. d) They are the primary site of photosynthesis, where the food is made

Acidic, basic and neutral substances

  1. 1. d) Baking soda solution
  2. 2. 2 — Basic
  3. 3. c) An olfactory indicator, whose smell changes
  4. 4.
    • lichens
    • lichen
  5. 5. b) It is acidic, or it is neutral
  6. 6.
    • acid-base indicator
    • acid base indicator
    • indicator
  7. 7. Red litmus paper → turns blue; Red rose extract → turns green; Turmeric paper → turns red
  8. 8. Lemon juice → Acidic; Tamarind water → Acidic; Vinegar → Acidic; Soap solution → Basic; Lime water → Basic; Washing powder solution → Basic; Sugar solution → Neutral; Salt solution → Neutral

Physical and chemical changes

  1. 1. a) The state of a substance may change, and no new substance is formed
  2. 2. d) A fuel, oxygen, and heat enough to reach the ignition temperature
  3. 3. d) They cannot be reversed
  4. 4. erosion
  5. 5. a) A chemical change — iron in the rock has turned into iron oxide
  6. 6. Melting an ice cube → Physical change; Crushing chalk into powder → Physical change; Folding paper into a shape → Physical change; Rusting of an iron nail → Chemical change; Burning a magnesium ribbon → Chemical change; Adding baking soda to vinegar → Chemical change; Cooking food → Chemical change
  7. 7. c) Both — the wax melting and evaporating are physical, and the vapour burning is chemical
  8. 8. c) It cuts off the supply of air, so the burning has no oxygen

Metals and non-metals

  1. 1. Nitrogen → goes into making fertilisers; Chlorine → used to purify water; Iodine → put on a wound as an antiseptic
  2. 2. c) Because those two names are for elements, and these materials are not elements
  3. 3. conduction
  4. 4. c) Water and air together
  5. 5. Malleability → can be beaten into thin sheets; Ductility → can be drawn into wires; Sonority → gives a ringing sound when struck
  6. 6. rust
  7. 7. b) Acidic
  8. 8. Copper → Metal; Aluminium → Metal; Iron → Metal; Magnesium → Metal; Sulfur → Non-metal; Carbon → Non-metal; Oxygen → Non-metal; Nitrogen → Non-metal

Heat transfer in nature

  1. 1. c) Heavy extraction for a growing population, and concrete surfaces that leave less room for water to soak in
  2. 2. Conduction → heat passes along, and the particles stay where they are; Convection → the heated particles themselves move, carrying the heat; Radiation → heat crosses with no medium to carry it
  3. 3. a) Radiation
  4. 4. d) It reflects most of the heat falling on it, while dark surfaces absorb more
  5. 5. c) Gravel, because the spaces between its particles are the widest
  6. 6. Steel → Good conductor of heat; Aluminium → Good conductor of heat; Wood → Poor conductor of heat; Glass → Poor conductor of heat; Clay → Poor conductor of heat; Air → Poor conductor of heat
  7. 7. infiltration
  8. 8.
    • aquifer
    • an aquifer
    • aquifers

Measuring time

  1. 1. d) Very rapid vibrations of a quartz crystal
  2. 2. b) 30 s
  3. 3. 240
  4. 4. 360
  5. 5. b) 60
  6. 6. 2
  7. 7.
    • time period
    • the time period
  8. 8. second

Speed and motion

  1. 1. c) Its average speed
  2. 2. Speedometer → shows how fast the vehicle is going right now; Odometer → shows how far the vehicle has travelled altogether
  3. 3. A train covering the same distance in each ten-minute interval → Uniform linear motion; A train running at an unchanging speed along a straight stretch → Uniform linear motion; A train covering different distances in successive ten-minute intervals → Non-uniform linear motion; A train pulling out of a station and picking up speed → Non-uniform linear motion; A train slowing down as it comes into a station → Non-uniform linear motion
  4. 4. 8
  5. 5. 20
  6. 6. a) Objects are seldom found holding a constant speed for long, which is why average speeds are used
  7. 7. 4
  8. 8. c) She has covered more distance in the same time, so she is the faster

Light, shadows and reflection

  1. 1. c) Both shadows are the same, because changing an object's colour does not change its shadow's colour
  2. 2. b) Upside down
  3. 3. a) Its three mirrors reflect each other's reflections, and turning it rearranges the pieces
  4. 4. a) A source of light, an opaque object, and a screen
  5. 5.
    • reflection
    • reflection of light
  6. 6. A pinhole camera → forms an inverted image; An opaque object → blocks light completely; A transparent object → lets light pass almost completely through; A shadow → the dark region formed behind an object
  7. 7. 3 — The image
  8. 8. c) So that it reads the right way round in the rear-view mirror of the vehicle ahead

Circuits and their components

  1. 1. c) It is open — a gap is left that the current cannot cross
  2. 2. d) The positive terminal
  3. 3. a) It glows just as before, because the circuit is still complete
  4. 4. 3 — Switch
  5. 5. Copper wire → Conductor; Metal key → Conductor; Aluminium foil → Conductor; Plastic scale → Insulator; Rubber eraser → Insulator; Wooden stick → Insulator
  6. 6. b) Copper costs less and there is plenty of it, and it conducts nearly as well
  7. 7. 1. The positive terminal of the cell 2. The switch, closed to ON 3. The filament of the lamp 4. The negative terminal of the cell
  8. 8. d) They are insulators, so they keep the current from reaching a person

The Earth, the Moon and the Sun

  1. 1. b) An eclipsed full Moon can be watched safely with the naked eye
  2. 2. a) It is tilted towards the Sun, so the sunlight is more intense and lasts more than 12 hours a day
  3. 3. 1. Your place turns into the sunlight, and the Sun rises 2. Your place is on the half facing the Sun — daytime 3. Your place turns out of the sunlight, and the Sun sets 4. Your place is on the half turned away from the Sun — night
  4. 4. b) The tilt of the Earth's axis, together with the Earth's spherical shape
  5. 5. 2 — The Earth
  6. 6. c) Anti-clockwise, which is from West to East
  7. 7. a) They lie close to the equator, where daylight and sunlight intensity vary little through the year
  8. 8. Solar eclipse → the Moon comes between the Sun and the Earth; Lunar eclipse → the Earth comes between the Sun and the Moon; A Moon completely inside the Earth's shadow → a total lunar eclipse, with the Moon turned dark red

Year 8 Science · www.arenapublications.com/learn