ScienceYear 7 Physics

Forces

Notes & Experiments

Name: ________________Teacher: ______________

YOU MUST KEEP THIS BOOK

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MY UNDERSTANDING CHECKLIST

I can… Textbook Pages

Before the Topic

After the Topic

What are Forces?Identify whether a force is contact or non-contact 14

Name and describe different types of forces 14 – 21

Describe forces as push and pull interactions between 2 objects 15

Balanced and Unbalanced ForcesUse arrows to represent forces 14Describe examples of systems with balanced/unbalanced forces 22 – 23

Calculate the resultant force in one dimension -

Weight and MassState the units of weight and mass 21Describe the effect of gravitational force on weight 21

Explain why weight changes on other planets but mass does not 20

FrictionGive examples of friction in everyday life 18

Describe the effect friction has on an object 18

Describe and investigate how different surfaces affect friction. -

Stretch Lesson: Hooke’s LawDescribe what is meant by the extension of a spring and tell you how to measure it

16 - 17

State that the extension of a spring is proportional to the force applied to it. 17

Investigate the effect of adding force to a spring on its’ extension -

MY SKILLS CHECKLIST

I can… Before the Topic After the TopicDraw and interpret force diagramsPlot a scatter graph and add a line of best fitDerive ideas about forces from observations

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KEY WORDS

Some of the key words and definitions are missing some information! Can you complete them?

Key Word Image/Diagram Definition

ForceA ________ or a _______ which acts in a particular direction.

ContactWhen two objects are ___________ each other

Non-Contact When two objects are not ____________ each other

Resultant Force

A measure of how _____________ the forces are on an object

Force Diagram A visual representation of a ________. An _____ is used to represent the force.

Balanced When forces acting on an object are equal and _________

Unbalanced When the forces acting on an object are not _________

Newton The unit of ________. It has the symbol _____

NewtonmeterA device used to measure _________

Weight The force acting __________ on an object. It

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happens as a result of the gravitational pull of the planet you are on.

MassThe amount of matter contained in an object. It is measured in ______ or ________

Gravity Name given to the pull on you towards the centre of the ________

Friction A force which always acts _________ the direction of motion

Extension

The change in length of a spring from its original length.

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Lesson 1: What are Forces?

Learning Objectives: Developing Identify whether a force is contact or non-contact Secure Name and describe different types of forces

Extending Describe forces as push and pull interactions between 2 objectsSCIENTIFIC SKILLS Derive ideas about forces from observations

Starter: What do you know about Forces?

On the mind map below write down everything you already know about Forces. Be ready to share your ideas with the class.

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Forces

Types of Forces

With your teacher complete the table below to identify different types of Forces.

Name of Force Description Example

ThrustThis can be any driving force, it may be a push or pull, but it could be an engine which forces an object forward.

This force affects every object on Earth. It is a force which pulls everything to the centre of the earth.

Force of human acting downwards

This force acts on objects when they are in contact with a surface, such as the ground. It can be reduced by ensuring both surfaces are smooth.

Rubbing hands together

Air Resistance / Drag

This is a force which acts in the air, it can slow objects down when they are moving against it. Or if harnessed could be used to move an object along.

This force acts between magnetic objects. It can either be an attractive or repulsive force.

Attraction of two magnets

TensionThis force acts on objects which have been stretched or extended. This force commonly acts in springs and ropes.

This is an upward force which acts in water, it acts on an object against its weight, and is why certain objects float.

Floating boat

Lift This is an upward force which enable aeroplanes to fly. It is caused by a pressure difference across the wings of the aeroplane.

This is an upward force provided by the ground. This force prevents objects sinking into the ground.

Upward force stopping table sinking

into floor

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Forces Worksheet

Label the forces in the following diagrams

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Key Ideas:

1. A force can be a push or a__________. on an object.2. A force can make an object change _______ or direction.3. The 2 main types of forces are __________ and non-contact.

a. ___________ only happen when 2 objects are touching each other e.g. Friction. b. ________________ don’t need the objects to be touching to happen e.g. Magnetic.

Investigation: Forces Circus

At each of the stations you should observe what is happening and use these observations to complete the diagrams and questions. Remember, you might not always be able to see forces so you must also think about the invisible physics!

Circle whether the force is contact or non-contact

Station 1: Floating PaperclipDraw a labelled diagram of what you are looking at:

1. Put a piece of paper between the magnet and the paper clip. What happens?

2. Why does the Paperclip need to be attached to a piece of thread?

3. Add an arrow to your diagram to show what would happen to the paperclip if the thread was cut. Can you explain why this would happen below:

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Station 2: Floating CorkDraw a labelled diagram of what you are looking at:

1. Name the force which is stopping the cork sinking? Can you describe it?

2. What would happen if I replaced the cork with a heavy rock?

3. Can you see any “pushing” or “pulling” forces in the demo? What are they and can you label them on your diagram?

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Station 3: Spinning MagnetUse the free magnet on the table. Can you make the hanging magnet spin without touching it?

In the box below sketch a diagram to show what you did to make the magnet spin:

1. What happened if you turned the magnet in your hand around and tried to spin the magnet?

2. Why do you think this happened?

3. Using your observations can you describe what would happen to the following pairs of magnets.

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Station 4: Masses on SpringsDraw a labelled diagram of what you can see:

1. Which of the springs was stretched the most? What value of mass was on the end?

2. How could you stretch the spring more than in the above examples?

3. Add arrows to your diagram to show which way the mass is pulling the spring.

4. What would happen if the mass fell off the spring? Would all the springs do the same thing?

Science Skill: Conclusions from your investigationUse your observations to decide if the following forces are contact or non-contact forces:

Force Contact Non-contactMagnetic (between magnet and paper clip)Tension (in string as it pulls the paperclip down)Upthrust (water pushing cork up)Weight (cork pushing down on water)Magnetic (between 2 magnets)Weight (masses pulling down on spring)Tension (in spring as it pulls masses up)

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Health and Safety Check!

I will wear goggles when using springs

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Can you correctly label the forces in the following diagrams?

STRETCH

Lesson 2: Balanced and Unbalanced Forces

Learning Objectives:Developing Use arrows to represent forcesSecure Describe examples of systems with balances/unbalanced forcesExtending Calculate the resultant force in one dimensionSCIENTIFIC SKILLS Draw and interpret force diagrams

Starter: Name the Force

STRETCH:

Additional Notes:

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

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………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

Science Skill: Adding forces (The Resultant Force)

Forces are measured in ____________ (N).

Forces can be ______________ or ____________.

You can add forces to find out the resultant force.

We represent forces with an arrow with a single head like this:

We represent the resultant force with an arrow with a double head like this:

Key Idea:

The Resultant Force is used to describe how unbalanced the forces are. (the bigger the resultant force, the more unbalanced the forces must be)

Worked Example:

The box below has 2 forces acting on it. 5N to the right and 3N to the left. Add the force arrows.

What is the size of the resultant force and what direction is it acting in?

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Task: Resultant Forces Worksheet

In each of the examples below calculate the resultant force and state its direction.

1. 2.

Resultant Force = …….………... Resultant Force = ……………...

3. 4.

Resultant Force = …….………... Resultant Force = …….………...

5. 6.

Resultant Force = …………... Resultant Force = …….………...

STRETCH:

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4N 10N

90N 110N600N 150N

25N 13N

125N

72N

5.2N

11.3N

50N 50N

103N

34N

Notes: Balanced and Unbalanced

Forces

Forces can be ______________ or ____________.

If the forces are balanced, then the object will stay ________________ or move at __________ speed.

If the forces are unbalanced, then the object will change ______________. Depending on the relative direction of the unbalanced force and the initial motion, the object could either _________ (speed up) or decelerate (slow down).

Simulation: http://phet.colorado.edu/sims/html/forces-and-motion-basics/latest/forces-and-motion-basics_en.html

Use the simulation to describe the motion observed in the following situations.

………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………….

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Resultant Force = …………...

…………………………………………………………………………………………………………………………

…….

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………

…….

Extension:

…………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………….

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…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………

…….

Summary: Balanced and Unbalanced Forces

Add force arrows the boxes below to show balanced and unbalanced forces:

BALANCED

UNBALANCED I

UNBALANCED II

UNBALANCED III

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This box will:

This box will:

This box will:

This box will:

Assessed Worksheet: Balanced and Unbalanced Forces

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Key Idea: The _______ the force arrow the ________ the force acting in that direction

CG Score: Next Steps:

20

STRETCH

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Lesson 3: Weight and Mass

Learning Objectives:Developing State the units of weight and massSecure Describe the effect of gravitational force on an objects weight Extending Explain why weight changes on other planets but mass does notScientific Skills Derive ideas about forces from observations

Starter: Calculate the resultant force

Calculate and draw on the resultant force for each of the boxes below.

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

…………………………………………………………………………………………………………………………………………………………….

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420N 120N 150N 174N

6.1N

11.1N

125N

72N

Weight and Mass

Weight and mass are two different things in physics.

Your mass is a measure of how much “stuff” (or matter) you have in your body. We measure mass in ________________(kg).

Your weight is the force exerted on your due to gravity (because you are on Earth). Because it is a force it is measured in ________________ (N).

Weight and mass are linked in the following relationship:

Weight (W )=×

Which can be represented in the following equation triangle:

On Earth; g has a value of 10N/kg

Worked Example:

Jonathan has a mass of 85kg. How much does he weigh on Earth?

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Calculations: Weight and Mass

1. Calculate the weight of an object with a mass of 50 kg on Earth where g is 10N/kg.

2. Calculate the weight if an object of 60 kg on Earth.

3. Work out the mass if an object on Earth that has a weight of 98N.

4. Calculate the mass of a person on Earth with a weight of 700N.

5. Calculate the value of g on the moon if the mass is 10kg and the weight is 16N

6. STRETCH: The value of g on Mercury is 3.8N/kg. Compare the weight of a 10kg object on Earth to being on Mercury.

PEER MARKING

(1 mark for working, 1 mark for answer, 1 mark for units)

Score [/18] Next Steps:

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Investigation: Weight on other planets

All cartons have a mass of 1kg.

Using the Newton Scale measure the weight of the juice carton on the different planets. Fill these into the table below. Leave the final column blank at this stage.

Planet Weight (N) g (N/kg)

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

The Moon

Now use your calculator and the appropriate equation to calculate the value of g on each of the planets. Fill this into the final column of your table.

g =

Science Skill: Conclusions from your investigation

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Health and Safety Check!

I will be careful to handle theheavy cartons with care.

Use your observations and results to answer the following questions:

1. On which planet would you weight the most?

2. On which planet would you weight the least?

3. On which planet would your weight be closest to what it in on Earth?

4. On which planets would you feel lighter than you do on Earth?

5. On which planets would you feel heavier than you do on Earth?

6. Where would you weight more; Saturn or Mercury? Explain your answer.

26My Mass is approximately _____________kg.

Using your results from the planet investigation. Plot a bar chart to show your weight on each of the planets in the solar system.

STRETCH

Lesson 4: Friction

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My Mass is approximately _____________kg.

Using your results from the planet investigation. Plot a bar chart to show your weight on each of the planets in the solar system.

Planets

Weight (N)

Learning Objectives:Developing Give examples of friction in everyday life Secure Describe the effect friction has on an object

Extending Describe and investigate how different surfaces affect friction

Scientific Skills Identify ways to improve an investigation

Starter: Slowing objects down

Label all the things that you could do to the following scenario to slow the car down:

…………………………………….

…………………………………………………………………………………………………………………………

…………………………………………………………………………………….

…………………………………….

…………………………………………………………………………………………………………………………

…………………………………………………………………………………….

………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………….

………………………………………………………………………………………………………………………….

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Friction Notes

Friction is a type of ________________. All Forces are measured in ____________ (N). It always acts _____________ to the direction that

an object is moving in.

Science Skill: Calculating Average Force

To try and improve the accuracy of our investigation we have taken multiple readings. We must now take an average of these results.

To calculate an average you must do the following:

Average= Attempt 1+Attempt2+Attempt 33

This is called finding the mean.

Use this formula to complete the table below.

Value 1 Value 2 Value 3 Average

2 6 4 4

6 2 8 5.3

5 9 4

11 14 10

12 11 15

18 22 23

56 78 62

Example Investigation: How does the type of surface affect friction?

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Aim:

The aim of this investigation is to find how the type of surface affects the amount of friction.

Variables:

Independent [Change] Type of Surface

Dependent [Measure] Amount of Friction

Control [Same] Object

Prediction:

I believe sandpaper is the roughest surface so predict it will have the most friction. I expect plastic to have the least friction as it is the smoothest surface.

Equipment & Set-up diagram:

Block of wood Newton meter Different types of surface

Method:

1. Collect your equipment and set up your investigation using the diagram above.2. Choose your first surface3. Pull the wooden block along the surface at a steady speed using the Newton meter.4. Take the reading on the Newton meter and write it in the table. 5. Repeat the experiment 3 times for each surface.

Surface TypeForce (N) Average

Force (N)Attempt 1 Attempt 2 Attempt 3Paper 4.0 4.5 3.8 4.1

Cardboard 8.3 14.6 7.8 8.1Sandpaper 14.2 12.8 13.6 13.5

Plastic 4.3 4.8 4.6 4.66. Change the surface and complete steps 3 and 4 again.

Results:

*Denotes an outlier. This value has been excluded from further average calculations.

Graph:

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Conclusion:

From the results above it is clear the sandpaper has the most friction. This matches my prediction. The reason for this is because sandpaper is the roughest surface. Paper on the other hand produced the least friction. Though, plastic also had very

small amount of friction. This is because both surfaces are fairly smooth compared to cardboard and

sandpaper.

Evaluation:

The experiment went fairly well. It was challenging to pull the wooden block along at constant speed and read the

Newton meter. Our second reading for cardboard was clearly an outlier. This may have been caused

by block becoming stuck on the fold in the cardboard.

Investigation: How does the mass of an object affect the amount of friction?

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X Axis (Independent Variable)

Y Axis (Dependent Variable)

Title

Surface type is a categoric variable, so a bar chart has been used to present the data

Scale chosen to use as much of graph paper as possible

Aim:

You are going to design an investigation to identify how the mass of an object affects the amount of friction. Additionally, using the example investigation write-up you will need to produce your own write-up for your investigation.

Variables:

Independent [Change]Dependent [Measure]

Control [Same]

Prediction:

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

Equipment & Set-up diagram:

Method:

How will you measure the amount of friction?

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….

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………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………

Results:

Tip: Make sure you add appropriate units to the results table headings.

Mass (…..)Force (…..) Average

Force (…..)Attempt 1 Attempt 2 Attempt 3

Graph:

Conclusion:

What did you find out from your investigation? Was it what you had predicted?

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

Evaluation:

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What worked well with your investigation? Did you encounter any problems with your investigation? Would you do anything differently next time?

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………

Assessed Worksheet: Friction

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You wake up on a strange planet where friction does not exist.

Can you tell the story of your day in the form of a comic?

CG Score: Next Steps:

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STRETCH

You wake up on a strange planet where friction does not exist.

Can you tell the story of your day in the form of a comic?

Lesson 5: Hooke’s Law

Learning Objectives:Developing Describe what is meant by the extension of a spring and explain

how to measure it Secure State that the extension of the spring is proportional to the force

applied to itExtending Investigate the effect of adding force to a spring on its’

extension. Scientific Skills Plot a scatter graph and add a line of best fit

Starter: Friction Arrows

Add arrows to the following pictures to show the direction of the Friction?

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STRETCH

[Hint: Remember it always does opposite the direction of motion]

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………

Investigation: Force and Extension.

The aim of this investigation is to identify the relationship between the force applied and how much an object extends.

Before we begin the investigation, we must understand what is meant by the term extension. On the diagram below, label where you will measure the extension of the spring in each example:

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Using this information complete the equation below.

Finish working out the extension of the spring for the following results table:

Mass (g) Force Added (N) Length of Spring (cm) Extension (cm)

0 0 20 0100 1 24 4200 2 28 8300 3 32400 4 36500 5 40600 6 44700 7 48800 8 52

Aim:

Your task is to design and carry out an investigation to find the relationship between force applied and extension for a spring.

Variables:

Independent

Dependent

Control

Prediction:

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Extension =

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

Equipment & Set-up diagram:

Method: …………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………

Results:

Using the outline below design your own results table. Remember to think about where the independent variable should go in your table and do not forget to add headings with appropriate units to the top of your columns.

Tip: Think carefully about the difference between mass and force applied.

Original Length of Spring =

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Mass (g) Force Added (N) Length of Spring (cm) Extension (cm)

Graph:

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Tip: Think carefully about which variable should go along the x and y axis.

Conclusion:

What did you find out from your investigation?

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Was it what you had predicted?

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

Evaluation:

What worked well with your investigation? Did you encounter any problems with your investigation?

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….…………………………………….……………………………………………………………………………………

Explain the relationship between Force and extension using your graph?

…………………………………….……………………………………………………………………………………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………….

42This is Hooke’s Law!

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If we kept adding force to the spring the graph would change and look like this:

Notice it is no longer a straight line. What do you think has happened to the spring and why?

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STRETCH

Forces: Past Paper Questions

Q1. Ellie has a set of scales and some weights as shown below.

Ellie puts two weights in pan X and one weight in pan Y. The scales balance.

(a) Which weights could be in pans X and Y?

pan X: .......... and ..........

pan Y: ..........1 mark

(b) Ellie removes all the weights from the scales.She then puts a cup on pan X.In which direction will pan Y move?

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

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(c) She puts weights into pan Y so the scales balance.

How much does the cup weigh?

................. N1 mark

(d) Ellie puts some water in the cup.She then adds some more weights to pan Y to make the scales balance.

(i) How much do the cup and water weigh?

................. N1 mark

(ii) How much does the water weigh?

................. N1 mark

maximum 5 marks

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Q2. (a) Tasha puts a small block of wood on a smooth surface.

She puts different forces on the block.The diagrams below show the size and direction of these forces.

Will each block move to the left, to the right or stay still?Tick the correct box in each row.

forces on block

(i)

1 mark

(ii)

1 mark

(iii)

1 mark

(iv)

1 mark

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Moves to the left

Moves to the right

Stays still

(b) (i) Which piece of equipment should Tasha use to measure the forces on the block?

Tick the correct box.

1 mark

(ii) Give the name of the equipment used to measure force.

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

maximum 6 marks

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Q3. The diagram below shows Jo hanging on a trapeze (swing) in a circus.

(a) (i) Which arrow, A, B, C or D, shows the direction of Jo’s weight?

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

(ii) Which arrow, A, B, C or D, shows the direction of the force of the rope onJo?

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

(b) Sara swings towards Jo.

Sara lets go of her trapeze and Jo catches her.

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(i) What happens to the downward force on the rope of Jo’s trapeze?Tick the correct box.

increases decreases stays the same there is no force

1 mark

(ii) Explain your answer.

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

(c) Jo lets go of the trapeze and both Sara and Jo fall into a safety net below them.

What happens to the downward force on the rope when Jo lets go?

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

maximum 5 marks

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Q4. (a) Nicola is trying out her new roller blades. Robert is pulling her along with a rope. Arrows A, B, C and D show the directions of four forces acting on Nicola.

(i) Which arrow shows the direction of the force of on Nicol’s Weight?Give the letter.

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

(ii) Which arrow shows the direction of the force of the rope on Nicola?Give the letter.

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

(b) Robert pulls Nicola at a steady speed of 2 metres per second. How far will Nicola travel in 10 seconds?

............... metres1 mark

(c) Nicola lets go of the rope and she slows down. Nicola’s Weight still acts.

Give the name of one other force still acting on Nicola after she lets go of the rope.

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

maximum 4 marks

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Q5. The drawings in parts (a), (b) and (c) show two teams of pupils in a tug-of-war.There is a ribbon tied to the middle of the rope.

(a) The sizes and directions of the forces of each team are shown.

team A team B

The ribbon stays above point X on the ground.Give the reason for this.

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

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

(b) The teams then pull with the forces shown below.

team A team B

Draw an arrow on the rope to show the direction in which the ribbon will move.1 mark

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(c) Later, the ribbon was to the left of point X as shown below.

team A team B

Why did the ribbon move towards the left?

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

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

(d) Team A practices by pulling a rope tied to a tree.

The team pulls with a force of 1200 N but the tree does not move.

What is the force of the tree on the rope?Tick the correct box.

1 mark

(e) The pupils do not slip because there is a force between their shoes and theground. What is the name of this force?

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

maximum 5 marks

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Q6. When a car is being driven along, two horizontal forces affect its motion.One is air resistance and the other is the forward force.

(a) (i) Explain how molecules in the air cause air resistance.

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

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

(ii) Explain why air resistance is larger when the car is travelling faster.

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

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

(b) (i) Compare the sizes of the forward force and the air resistance when the car is speeding up.

The forward force is .............................................................................

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

(ii) Compare the sizes of the two forces while the car is moving at a steady 30 miles per hour.

The forward force is ............................................................................

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

(c) The forward force has to be larger when the car is travelling at a steady 60 mph than when it is travelling at a steady 30 mph. Why is this?

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

......................................................................................................................1 ma

Maximum 5 marks

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Q7. Jack and Aneesa dropped a steel ball into trays of damp sand.They measured the depth of the craters made by the steel ball.

not to scaleTheir results are shown in the table below.

height the ball wasdropped from (cm)

depth of crater (cm)

Jack’s results Aneesa’sresults

10 1.1 1.2 0.8

20 1.4 1.5 1.4

30 1.6 1.6 1.5

40 1.8 1.7 1.8

50 2.0 2.1 2.1

(a) Use information in the table to answer the questions below.

(i) What was the independent variable that Jack and Aneesa changed in their investigation?

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

(ii) Why was Jack’s investigation better than Aneesa’s?

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

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(b) Look at the results in the table.What is the relationship between the height the ball was dropped from and the depth of the crater?

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

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

(c) Aneesa said that they made sure the investigation was fair.

Suggest two variables they must have kept the same to make their investigation fair.

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

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

(d) (i) Jack removed the steel ball using his fingers. Then he measured the depth of the crater.Aneesa said he should use a magnet instead of his fingers.

Explain why using a magnet to remove the ball would improve the investigation.

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

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

(ii) Jack said that the ball could be dropped using an electromagnet instead of dropping it by hand.

Explain why this would improve the investigation.

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

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

maximum 7 marks

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