Name: Science set:_____________ Science Teacher : ___________________________ Form: _________

Year 8 Science

Workbook. To be completed at home on Monday 5th and Tuesday 6th June. In order to reach your target grade, you need to complete the relevant number of marks according to your pathway.

Pathway Target number of marks to achieve

1 60 2 70 3 80 4 90 5 100 6 120 7 140 8 160

Year 8 Biology Digestive System Q1. The diagram shows some of the organs of the human body.

(a) Give the names of two labelled parts where food is digested.

.................................................... and ................................................... 1 mark

(b) Why do we need to chew our food and mix it with saliva?

.....................................................................................................................

.....................................................................................................................

..................................................................................................................... 2 marks

(c) (i) Draw one line from each bad habit to the organ it harms.

3 marks

(ii) Which organ in the list below can be harmed if we eat too much fat? Tick the correct box.

brain

heart

lung

ribs

1 mark Maximum 7 marks

Q2. (a) Pineapple juice contains a substance that speeds up the digestion of protein.

(i) What is the name for substances that speed up digestion?

............................................................ 1 mark

(ii) What happens to a molecule of protein during digestion?

...............................................................................................................

............................................................................................................... 1 mark

(b) Asim did an experiment to investigate the digestion of gelatin. Gelatin is the protein in jelly. In test tubes A and B he used one cube of jelly in each. In test tube C he used one cube of jelly that he had chopped up.

A B C 5 g jelly cube 5 g jelly cube 5 g jelly cube + + chopped into 15 cm3 15 cm3 fresh pieces cold water pineapple + juice 15 cm3 fresh pineapple juice

He recorded how long it took for the jelly to be digested in each test tube. The table below shows his results.

test tube result

A not digested after 2 hours

B jelly digested in 2 hours

C jelly digested in 1 hour (i) What was the purpose of test tube A?

...............................................................................................................

............................................................................................................... 1 mark

(ii) It is helpful to chew your food. How do the results in test tube C show this?

...............................................................................................................

............................................................................................................... 1 mark

(c) The substances that speed up digestion stop working when they have been boiled.

(i) What does Asim need to put in a fourth test tube to test this in his experiment? Label test tube D. Test tubes A, B and C contain the same as in the first experiment.

A B C D 5 g jelly 5 g jelly cube 5 g jelly cube ............................ cube + chopped into + 15 cm3 fresh pieces ............................ 15 cm3 pineapple + + cold water juice 15 cm3 fresh pineapple ............................ ............................ ............................

2 marks (ii) Predict what Asim would observe in test tube D after 2 hours.

............................................................................................................... 1 mark

maximum 7 marks

Inheritance

Q3. The diagram shows two families. Some of the people in the diagram have freckles.

family A family B

(a) (i) Which children are most likely to have freckles? Tick the correct boxes.

Richard Simon Katie Penny Becca

1 mark

(ii) How did you decide?

.............................................................................................................

............................................................................................................. 1 mark

(iii) Suggest why Bill does not have freckles.

.............................................................................................................

............................................................................................................. 1 mark

(b) (i) Which two cells pass on information from parents to their children? Tick the two correct boxes.

bone cell cheek cell

egg cell muscle cell

red blood cell sperm cell 1 mark

(ii) Which organ system produces these two cells? Tick the correct box.

circulatory system

digestive system

reproductive system

respiratory system 1 mark

maximum 5 marks

Q4. The drawings show identical twins, Sara and Helen, and their parents.

(a) (i) Sara and Helen have blue eyes like their mother.

Describe how genetic information is passed on from a parent to a child.

................................................................................................................

................................................................................................................

................................................................................................................

................................................................................................................ 2 marks

(ii) Sara and Helen have brown hair like their father and blue eyes like their mother.

Why do children have characteristics of both parents?

................................................................................................................

................................................................................................................ 1 mark

(b) Sara and Helen are identical twins.

Why do they have identical characteristics?

............................................................................................................................

........................................................................................................................ 1 mark

(c) Sara now spends a lot of her time working outdoors in a hot country. Helen now works in an office in England.

The table shows information about three human characteristics.

characteristic Is it identical for Sara and Helen?

eye colour yes

skin colour no

weight no Explain why their eye colour is identical but their weight and skin colour are not identical.

.........................................................................................................................

.........................................................................................................................

.........................................................................................................................

......................................................................................................................... 2 marks

maximum 6 marks

Smoking

Q5. In 2007, a new law came in to stop people smoking in public buildings.

(a) Smoking can be very harmful.

Which three problems can be caused by smoking?

Tick the three correct boxes.

being out of breath easily

lung cancer

being overweight

food poisoning

heart disease

2 marks

(b) Some scientists investigate ‘passive smoking’. Passive smoking is when people breathe in smoke from other people’s cigarettes. They checked the health of three groups of people.

(i) Which group of people breathe in the least cigarette smoke? Tick the correct box.

group A group B group C 1 mark

(ii) Which two groups will help scientists find out the effects of passive smoking? Tick the two correct boxes.

group A group B group C 1 mark

(c) People in group B are likely to have similar health problems to people in group C. Explain why.

......................................................................................................................

...................................................................................................................... 1 mark

(d) Four scientists investigated passive smoking. The table below shows the number of people each scientist studied from each group.

scientist group A group B group C

David 289 3 18

Olga 8 6 11

Peter 402 399 403

Mary 15 210 511

Which scientist is likely to get the most reliable results? Tick the correct box.

David

Olga

Peter

Mary

1 mark

maximum 6 marks

Bacterial Growth

Q6. Jane stored some milk at room temperature for five days in a sealed container. She used a pH sensor and data logger to record the pH of the milk for 5 days.

Her results are shown below.

graph 1

(a) Jane predicted that the number of live bacteria in the milk would change as shown below.

graph 2

(i) Suggest one reason why the number of live bacteria would start to decrease after 3 days.

...............................................................................................................

............................................................................................................... 1 mark

(ii) What evidence from graph 1 suggests that there were still some live bacteria in the milk on day 5?

...............................................................................................................

............................................................................................................... 1 mark

(b) Jane put some fresh milk in a sealed container in the fridge. She measured the pH of the milk every day for five days.

(i) On graph 3 below, draw a line to show the pH of the refrigerated milk for five days.

graph 3

2 marks

(ii) On graph 4 below, draw a line to predict how the number of live bacteria in refrigerated milk will change over five days.

graph 4

1 mark

maximum 5 marks

Breathing Q7. The drawing below shows the human rib cage.

(a) The rib cage protects organs in the chest.

Give the names of two organs in the chest.

1. ................................................................

2. ................................................................ 2 marks

(b) The ribs are attached to the breast bone by cartilage which bends easily. This lets the space in the chest get bigger.

Why is it important that the space can get bigger?

........................................................................................................................

........................................................................................................................ 1 mark

(c) The drawings below show parts of three different organ systems.

Draw a line from each organ system to its function. Draw only three lines.

3 marks

maximum 6 marks

Q8. Joanne measured the volume of air she breathed in and out of her lungs. She used the machine shown in the photograph below.

The graphs represent the volume of air Joanne breathed in and out with each breath before and during exercise.

(a) During exercise Joanne breathed more air in and out of her lungs than before exercising.

(i) How much more air did Joanne breathe in with each breath during exercise?

.................... cm3

1 mark (ii) Explain fully why Joanne needed to breathe in more air during exercise.

.............................................................................................................

.............................................................................................................

.............................................................................................................

.............................................................................................................

.............................................................................................................

............................................................................................................. 3 marks

(b) (i) As Joanne exercised, the volume of air she breathed in and out increased. Give one other way Joanne’s breathing changed during exercise.

.............................................................................................................

............................................................................................................. 1 mark

(ii) How does the graph show this other change?

.............................................................................................................

............................................................................................................. 1 mark

maximum 6 marks

Photosynthesis

Q9. The drawing below shows Rebekah pulling a turnip out of the ground.

(a) Which arrow, A, B, C or D, shows the direction of force of Rebekah’s hand on the turnip?

................. 1 mark

(b) The drawing below shows root maggots eating a turnip. The maggots damage the roots.

Damaged roots do not grow very well.

Complete the sentence below.

Damaged roots cannot take up as much ............................................... and

............................................... from the soil. 2 marks

(c) The drawing below shows a food chain including a rove beetle.

not to scale

Which word describes a rove beetle? Tick the correct box.

herbivore

predator

prey

producer

1 mark

(d) Turnip plants make food by photosynthesis.

(i) Which part of a plant makes food?

............................................... 1 mark

(ii) What will the turnip plant use stored food for?

............................................................................................................. 1 mark

maximum 6 marks

Q10. A garden centre has two types of the same plant for sale.

Chlorophyll makes a plant leaf green.

(a) At the end of the summer, the normal plants had grown more than those with variegated leaves. All the plants had been grown in the same conditions.

(i) Explain why plants with normal leaves grow more than plants with variegated leaves.

.............................................................................................................

.............................................................................................................

............................................................................................................. 2 marks

(ii) Describe an investigation you could do to show how much more a normal plant grows compared with a variegated plant over a six-week period.

In your answer, you must clearly identify: • the independent variable (IV) • the dependent variable (DV) • the variables to control (CV) • how you will calculate the end result.

.............................................................................................................

.............................................................................................................

.............................................................................................................

.............................................................................................................

.............................................................................................................

.............................................................................................................

.............................................................................................................

............................................................................................................. 4 marks

(b) What process do plants carry out in the light and in the dark to release energy? Tick the correct box.

photosynthesis

respiration

absorption

dispersal

1 mark

maximum 7 marks

Elements Q1. (a) The drawings below show three objects made from copper.

Draw a line from each object to the reason for using copper for that object. Draw only three lines.

3 marks

(b) Brass is a mixture of copper and zinc. Some keys are made from brass

Why is brass more suitable than copper for a key? Tick the two correct boxes.

Brass does not bend as easily as copper.

Brass is a paler colour than copper.

Brass is harder than copper.

Brass is not as shiny as copper.

Brass is not such a good conductor of electricity as copper.

Brass is not such a good conductor of heat as copper.

2 marks

(c) Zinc melts at 420°C.

Copper melts at 1085°C.

A scientist heated a mixture of pieces of zinc and pieces of copper to 600°C in a dish.

What would be in the dish at 600°C?

liquid zinc and liquid copper

liquid zinc and solid copper

solid zinc and liquid copper

solid zinc and solid copper

1 mark

maximum 6 marks

Types of reaction

Q2. Simon made two candles from the same amount of wax. He drew lines on both candles.

(a) What would Simon use to measure the distance between the lines?

.......................................... 1 mark

(b) He timed how long candle 1 took to burn. His results are shown below.

(i) How long would it take for candle 1 to burn from C to D? Write your answer in the table.

part that burned time for candle 1 to burn (minutes)

A to B 30

B to C 30

C to D

D to E 30

1 mark

(ii) Simon timed how long candle 2 took to burn.

How long would it take for candle 2 to burn from A to B and from D to E? Write your answers in the table.

part that burned time for candle 2 to burn (minutes)

A to B

B to C 20

C to D 40

D to E

2 marks

(c) Simon wanted to use a candle to measure time. He made candle 3 the same size as candle 1.

Why is candle 3 more useful than candle 1 for measuring time?

........................................................................................................................

........................................................................................................................ 1 mark

maximum 5 marks

Elements, compounds and mixtures

Q3. (a) Samantha opened a tin of white paint. The paint consisted of a liquid and particles of titanium dioxide that are insoluble in the liquid. The paint had separated into two layers, as shown below.

(i) What type of substance is the paint? Tick the correct box.

a compound an element

a mixture 1 mark

(ii) What type of substance is titanium dioxide? Tick the correct box.

a compound an element

a mixture 1 mark

(iii) Why did the particles of insoluble titanium dioxide sink to the bottom?

.............................................................................................................

............................................................................................................. 1 mark

(b) Samantha stirred the paint and used it to paint a window frame. She got some of the paint on the glass.

Samantha could not get the paint off the glass with water. When she used a different liquid called white spirit the paint came off.

Why could she remove the paint with white spirit but not with water?

.....................................................................................................................

..................................................................................................................... 1 mark

maximum 4 marks

Q4

The porous pot shown in diagrams 1 and 2 lets gas molecules pass through the walls. In diagram 2 a beaker containing hydrogen is placed over the porous pot. The water levels in the U-tube quickly change.

Four statements about the movement of gas molecules are given below.

A – no molecules are moving into or moving out of the porous pot

B – same number of gas molecules are moving into the porous pot as are moving out

C – more gas molecules are moving into the porous pot than are moving out

D – fewer gas molecules are moving into the porous pot than are moving out

(a) Which statement, A, B, C or D, applies to:

(i) Diagram 1? ......................................................................................... 1 mark

(ii) Diagram 2 just after the beaker is put in position?............................... 1 mark

(b) What does the experiment suggest about the average speed of hydrogen molecules compared with the average speed of molecules in the air?

Hydrogen molecules ..................................................................................... 1 mark

(c) The beaker is removed from around the porous pot.

(i) How does the water level in the left hand part of the U-tube change?

............................................................................................................. 1 mark

(ii) Explain your answer in terms of the movement of molecules.

.............................................................................................................

............................................................................................................. 1 mark

(d) Air contains oxygen, nitrogen, argon, some water vapour, and a little carbon dioxide.

Complete each row in the following table by ticking one box and by stating the number of atoms in one molecule of the substance.

The first row has been done for you.

4 marks

Maximum 9 marks

Earths resources

Q5.

(a) From the substances named above, give:

(i) the name of a metal;

............................................................................................................. 1 mark

(ii) the name of an element which is a non-metal;

............................................................................................................. 1 mark

(iii) the name of an element which will rust;

............................................................................................................. 1 mark

(iv) the name of a compound.

............................................................................................................. 1 mark

(b) When magnesium and sulphur are heated together, they react. Write the name of the compound which is formed when magnesium reacts with sulphur.

...................................................................................................................... 1 mark

Maximum 5 marks

Chemical energy

Q6. (a) Methane can be a gas, a liquid or a solid. In the diagram below, arrows P, Q, R and S represent changes of state.

The boxes on the right show the arrangement of particles of methane in the three different physical states. Each circle represents a particle of methane.

(i) Draw a line from each physical state of methane to the arrangement of particles in that physical state. Draw only three lines.

1 mark

(ii) Arrows P, Q, R and S represent changes of state. Which arrow represents:

evaporation? ............................................................

melting? ................................................................... 2 marks

(b) Methane is the main compound in natural gas. The scale below shows the melting point and the boiling point of methane.

Methane has three physical states: solid, liquid and gas.

(i) What is the physical state of methane at –170°C?

............................................................. 1 mark

(ii) The formula of methane is CH4. The symbols for the two elements in methane are C and H.

Give the names of these two elements.

element C .............................................

element H ............................................ 2 marks

(iii) When methane burns, it reacts with oxygen. One of the products is water, H2O.

Give the name of the other product.

.............................................................. 1 mark

Maximum 7 marks

Particle model

Q7. The diagrams represent the arrangement of atoms or molecules in four different substances, A, B, C and D.

not to scale

Each of the circles, , and represents an atom of a different element.

(a) (i) Which substance is a compound?

………… 1 mark

(ii) Which substance is a mixture?

………… 1 mark

(iii) Which two substances are elements?

………… and ………… 1 mark

(iv) Which two substances could be good thermal conductors?

………… and ………… 1 mark

(v) Which substance could be carbon dioxide?

………… 1 mark

(b) The following experiment was set up. Test-tubes containing substances B and C were placed together as shown. The substances did not react. They were left for five minutes.

(i) How many molecules are there in the mixture compared to the total number in substances B and C?

……………………………………….………………………………………. 1 mark

(ii) Complete the diagram which is a model of this experiment.

1 mark

Maximum 7 marks

Earths resources Q8

The exhaust gases of a car with a petrol engine are analysed during its ‘MOT test’. The results are shown below.

gas % volume

carbon monoxide

carbon dioxide

oxygen

other gases

3.0

13.0

0.4

83.6

(a) The air going into the engine contains about 20% of oxygen. Explain why there is only 0.4% of oxygen in the exhaust gases coming out of the car engine.

....................................................................................................................

.................................................................................................................... 1 mark

(b) (i) Petrol is a mixture of compounds which contains only carbon and hydrogen. Complete combustion of petrol produces carbon dioxide and one other substance. What is this other substance?

............................................................................................................. 1 mark

(ii) When petrol is burned in the car engine, carbon monoxide is produced as well as carbon dioxide.

Explain why carbon monoxide is dangerous and may kill you.

.............................................................................................................

............................................................................................................. 1 mark

Maximum 3 marks

The Earth’s atmosphere Q9

A headline from a newspaper is shown below.

Some countries claim that acid rain caused by power stations in Britain damages their forests. Others argue that coal-burning power stations produce cheap electricity and that plants can stand some level of acid rain.

Imagine you are planning a laboratory investigation of the claim:

‘plants can stand some level of acid rain’.

Assume you have access to whatever laboratory equipment you need, including:

• seeds

• acid

• seed trays

• soil

Plan a laboratory investigation to test the claim that ‘plants can stand some level of acid rain’.

(a) Name a factor you would need to vary in your investigation. (This is the independent variable.)

..................................................................................................................... 1 mark

(b) (i) What factor would you examine to see the effect? (This is the dependent variable.)

.............................................................................................................

............................................................................................................. 1 mark

(ii) How could you measure this dependent variable?

............................................................................................................. 1 mark

(c) Suggest one factor you would control to ensure that your investigation is fair.

..................................................................................................................... 1 mark

Maximum 4 marks

Q10.This question is about the Earth’s atmosphere today.

(a) The bar chart shows the percentage by mass of the gases in dry air from the atmosphere.

Gases

(i) What percentage of the atmosphere is gas A? ........................................ % (1)

(ii) Use gases from the box to answer this question.

bromine hydrogen nitrogen oxygen

Name gas A and gas B shown on the bar chart.

Gas A: ......................................................................

Gas B: ...................................................................... (2)

(b) The concentration of carbon dioxide in the atmosphere has changed.

The graph shows how the concentration of carbon dioxide has changed since 1800.

Year

(i) Describe how the concentration of carbon dioxide has changed since 1800.

...............................................................................................................

...............................................................................................................

...............................................................................................................

............................................................................................................... (2)

(ii) Complete the following sentence.

The main process that has caused the change in carbon dioxide is the burning

of ..................................................................................... . (1)

(Total 6 marks)

Q11. Supermarkets in the UK have been advised by the Government to stop giving plastic bags to customers. The Government states that this is because plastic bags use up resources that are not renewable and that the manufacture of plastic bags produces carbon dioxide. Most of these plastic bags are made from poly(ethene). The table shows methods to deal with large numbers of used plastic bags.

Method Description of what happens to the plastic bag

Reused used again by the customer

Recycled collected, transported, washed and melted to make new plastic items

Burned collected, transported and burnt to release heat energy

Dumped mixed with other household waste, collected, transported and disposed of at a landfill site

Use the information and your knowledge and understanding to briefly give one advantage and one disadvantage for each of these methods.

Reused ...................................................................................................................

.................................................................................................................................

.................................................................................................................................

Recycled .................................................................................................................

.................................................................................................................................

.................................................................................................................................

Burned ....................................................................................................................

.................................................................................................................................

.................................................................................................................................

Dumped ..................................................................................................................

.................................................................................................................................

................................................................................................................................. (4)

(Total 4 marks)

Physics Heating and Cooling

Q1. A company has made a new material called ‘Wellwarm’. They want to use ‘Wellwarm’ to make coats.

(a) A scientist tested ‘Wellwarm’ to see how well it insulated a beaker of hot water. She tested ‘Wellwarm’ and three other materials as shown below.

material A material B material C material D

She wrapped each beaker in a different material. She recorded the temperature at the start and 20 minutes later.

(i) What was the independent variable that the scientist changed?

............................................................................................................... 1 mark

(ii) What was the dependent variable that the scientist measured during the investigation?

............................................................................................................... 1 mark

(b) The results of the investigation are shown below.

time temperature of water (°C) wrapped in

(minutes) material A material B material C material D

0 60 60 60 60

20 34 40 38 36

(i) The scientist said that the ‘Wellwarm’ material is the best insulator. Which material was ‘Wellwarm’? Use the results to help you. Tick the correct box.

A B C D 1 mark

(ii) Use the evidence in the results table to explain your choice.

...............................................................................................................

............................................................................................................... 1 mark

(c) The company made a coat from each of the four materials they tested.

A person tested the different coats by wearing each one in a cold room. He measured the temperature inside each coat for 30 minutes.

Write down two other variables that should be controlled to make this a fair test.

1. .................................................................................................................... 1 mark

2. .................................................................................................................... 1 mark

(d) Write down one thing the scientists should do to make sure the person testing the coats is safe.

........................................................................................................................ 1 mark

(e) Suggest one advantage of using a temperature sensor and data logger instead of a thermometer in this experiment.

........................................................................................................................

........................................................................................................................ 1 mark

maximum 8 marks

Q2. John used an electrical heater to heat a cup of water. He kept stirring the water. When the temperature reached 20°C, he started his stopwatch and measured the temperature of the water every half minute.

He switched off the heater after 4 minutes, but continued to record the temperature. His results are shown in the table.

One measurement is missing and another appears to be wrong.

Time (minutes) Temperature (ºC)

0.0 20

0.5 26

1.0 31

1.5 36

2.0 41

2.5 46

3.0

3.5 57

4.0 56

4.5 58

5.0 59

5.5 59

(a) Use the results in the table to draw a graph on the grid. Label the axes. Plot the points and draw a smooth curve of best fit.

4 marks

(b) From your curve, estimate the temperature of the water after three minutes.

............°C 1 mark

maximum 5 marks

Waves Q3. (a) Water waves are transverse waves. Sound waves are longitudinal waves.

(i) Explain the difference between a transverse wave and a longitudinal wave.

You may include labelled diagrams in your answer.

........................................................................................................................

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........................................................................................................................

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........................................................................................................................

........................................................................................................................ (3)

(ii) Name one type of wave that may be either transverse or longitudinal.

........................................................................................................................ (1)

(b) The diagram shows water waves in a ripple tank moving towards a gap in a barrier.

The water waves diffract as they pass through the gap.

Complete the diagram to show the diffracted water waves.

(1)

(c) A television is switched on inside a room. A person outside the room can hear the television, but only when the door is open.

When the door is open, the person can hear the sound but cannot see the television.

Explain why.

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ (2)

(Total 7 marks) Magnets

Q4. A compass needle is a small magnet with a North pole, N, and a South pole, S.

Ruth placed two compasses onto a piece of card. Both compass needles pointed in the direction shown below.

(a) Ruth placed a bar magnet with its South pole between the two compasses. The compass needles moved as shown below.

On the diagram below, label the North pole and South pole of each compass needle. Use the letters N and S.

1 mark

(b) Ruth turned the bar magnet round so that the North pole was between the two compasses.

On the diagram below, label the North pole and South pole of each compass needle now. Use the letters N and S.

1 mark

(c) Ruth repeated her experiment with an aluminium bar instead of a bar magnet.

What happened to the compass needles?

..................................................................................................................... 1 mark

maximum 3 marks

Q5. David put two bars of iron close to each other. There was no magnetic force between them. David recorded the result as shown below.

(a) David did three other tests. Tick the correct box to show the result for each test.

(i)

1 mark

(ii)

1 mark

(iii)

1 mark

(b) David then did two experiments with magnets.

The tick in each box shows David’s results in each experiment.

Label the missing poles on each magnet to match David’s results.

(i)

1 mark

(ii)

1 mark

maximum 5 marks

Q6. (a) Debbie put a paper cup into a glass beaker. She glued a magnet in the bottom of the paper cup. She glued another magnet in the bottom of the beaker. The magnets repelled.

diagram A not to scale

What two forces act on the paper cup and its contents to keep it in this position?

1. ........................................................... 1 mark

2. ........................................................... 1 mark

(b) Debbie put 5 g of aluminium rivets into the paper cup. It moved down a little as shown in diagram B.

diagram B not to scale

Debbie plotted a graph to show how the mass of aluminium rivets affected the distance the cup moved down.

(i) Use the graph to find the mass that made the cup move down 4 mm.

............... g 1 mark

(ii) Why did the graph stay flat with masses greater than 40 g?

............................................................................................................. 1 mark

(c) Debbie removed the 5 g of aluminium rivets and put 5 g of iron nails into the cup.

diagram C not to scale

The paper cup moved down more with 5 g of iron nails than with 5 g of aluminium

rivets as shown in diagram C. Give the reason for this.

.....................................................................................................................

..................................................................................................................... 1 mark

maximum 5 marks Electromagnets

Q7. David made two electromagnets as shown below. He used paper-clips to test the strength of each electromagnet. He switched on the power supply in both circuits.

(a) How can you tell that the strength of both electromagnets is the same?

......................................................................................................................

...................................................................................................................... 1 mark

(b) David switched off the power supply in both circuits. The paper-clips fell off the iron core, but not off the steel core.

Why is iron used, rather than steel, for the core of an electromagnet? Use the diagrams above to help you.

......................................................................................................................

...................................................................................................................... 1 mark

(c) David used a sensor to measure the strength of an electromagnet.

He placed the sensor 25 mm from the electromagnet and increased the current in the coil.

He repeated the experiment with the sensor 50 mm from the electromagnet.

The graph below shows his results.

(i) How did the distance of the sensor from the electromagnet affect the reading on the sensor?

................................................................................................................

................................................................................................................ 1 mark

(ii) How did the size of the current in the coil affect the strength of the electromagnet?

................................................................................................................

................................................................................................................ 1 mark

(iii) What else could David do to an electromagnet to change its strength?

................................................................................................................

................................................................................................................ 1 mark

maximum 5 marks

Q8. The diagram shows an electromagnet used in a door lock.

(a) The push switch is closed and the door unlocks. Explain in detail how this happens.

......................................................................................................................

......................................................................................................................

......................................................................................................................

......................................................................................................................

...................................................................................................................... 3 marks

(b) The switch is released and the door locks. Explain in detail how this happens.

......................................................................................................................

......................................................................................................................

......................................................................................................................

2 marks Maximum 5 marks

Q9. Mary used the apparatus below to test the strength of an electromagnet. She used the reading on the newton meter to measure the force of the magnet on the iron disc.

(a) Explain why the reading on the newton meter increases when a current passes through the coil.

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ 2 marks

(b) When a current passes through the coil, some of the electrical energy is changed to thermal energy. What would happen to the coil if the current passing through it was too large?

........................................................................................................................ 1 mark

(c) Mary made two electromagnets, one with 100 turns of wire in the coil and one with 200 turns. She varied the current through the coil of each electromagnet. She measured the force of each electromagnet on the iron disc. The graph shows her results.

Write two conclusions that Mary could make from these results.

1. ....................................................................................................................

........................................................................................................................

2. ....................................................................................................................

........................................................................................................................ 2 marks

maximum 5 marks

Speed

Q10. The graph shows how the speed of a 0.1 kg mass changes as it falls.

(a) Read from the graph the speed of the mass at 0.4 s and 0.8 s. Use your results to work out the average speed of the mass between 0 and 0.4 s and then between 0 and 0.8 s. Give the units.

(i) final speed at 0.4 s = ............................

average speed between 0 and 0.4 s = ................................... 1 mark

(ii) final speed at 0.8 s = ............................

average speed between 0 and 0.8 s = ................................... 1 mark

(b) Using the average speeds calculated in (a), work out how far the mass falls in:

(i) 0.4 s

............................................................................................................. 1 mark

(ii) 0.8 s

............................................................................................................. 1 mark

(c) Complete the sentence:

If the mass falls for double the time, it will fall .............................................

times as far 1 mark

Maximum 5 marks

Q11. The drawing below shows a space buggy on the surface of Mars.

(a) The distance between Earth and Mars is 192 000 000 km.

It took a spacecraft 200 days to take the buggy from Earth to Mars.

Calculate the speed at which the spacecraft travelled.

Give the unit.

.........................................................................................................................

......................................................................................................................... 2 marks

(b) The weight of the buggy was 105 N on Earth and 40 N on Mars.

Why was the weight of the buggy less on Mars than on Earth?

.........................................................................................................................

......................................................................................................................... 1 mark

(c) The buggy uses solar panels to generate electrical energy.

The solar panels generate less electrical energy on Mars than on Earth.

Give a reason why.

.........................................................................................................................

......................................................................................................................... 1 mark

(d) The weight of the buggy was 40 N on Mars. When the buggy landed on Mars it rested on an area of 0.025 m2.

Calculate the pressure exerted by the buggy on the surface of Mars.

Give the unit.

.........................................................................................................................

......................................................................................................................... 2 marks

maximum 6 marks