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ACTIVITY 1: FORCES AROUND YOU

Complete the following passage to show your understanding of forces.
A …………………… is a push, a …………………. or a twist. A force can change the
speed, direction or …………………………. of an object.
Forces are classified as ………………….. forces or ………………………..forces.
Friction is an example of a ………………………. force because it is caused when two
surfaces are in contact with each other and trying to slide across each other.
…………………………... forces include gravity, …………………….. and electrostatic
forces. We use the term ‘field’ to describe forces that act a distance (i.e. not caused by
contact). We refer to the field that exerts a force on a mass, magnetic substance or a
charged object as gravitational, magnetic and electric fields respectively.

Carry out the following investigation
PART A: CONTACT FORCES
Use the table tennis ball and a straw to answer the following questions.
1. What happens if you blow on the ball when it is moving towards you?
………….……………………………………………………………………………………….
2. What happens if you blow on the ball when it is moving away from you
………….……………………………………………………………………………………….
3. What happens if you blow on it when it is moving across in front of you?
………….……………………………………………………………………………………….
4. You might want to play a game of ‘blowball’ in a group of four, with two in each team.
Use a straw each and set up two goals and see who scores the most goals.
PART B: NON-CONTACT (FIELD) FORCES
1. Gravitational forces:
Collect a 20 coin and cut out a piece of paper the size of a 20 cent coin.
(a) Drop the paper and 20 cent coin from the same height at the same time. Write
an inference to explain what happened in terms of any forces acting.
….……………………………………………………………………………………
….……………………………………………………………………………………
(b) Roll the paper into a tight ball repeat the experiment. Write an inference to
explain what happened in terms of any forces acting on the two objects. Be
sure to distinguish between the contact and non-contact forces.
….……………………………………………………………………………………
….……………………………………………………………………………………
….……………………………………………………………………………………
….……………………………………………………………………………………
2. Electrostatic forces:
Tear a piece of paper into small bits and rub a plastic pen on your jumper.
(a) What happens when you bring the pen near the pieces of paper?
….……………………………………………………………………………………
….……………………………………………………………………………………
(b) How can you tell that the electrostatic force can act a distance?
….……………………………………………………………………………………
….……………………………………………………………………………………
3. Magnetic forces:
Collect two bar magnets. Feel what happens as you bring the north pole of one
magnet close to the north pole of the other magnet. Repeat the experiment with two
south poles.
Write a generalisation describing the forces that act between two like poles.
…………………………………………………………………………………………….
…………………………………………………………………………………………….
PART C: MEASURING FORCES

Collect several different spring balances, e.g. 5 N, 20 N and 50 N. Measure the forces
involved in at least 10 activities, e.g. opening a cupboard door, lifting a shoe, dragging
a chair, sliding a drawer open, lifting a pencil case, pulling a pencil case along your
desk, pulling sticky tape off the bench, opening a can of soft drink, etc. NB. You should
always use the spring balance with the largest range and use smaller ones for greater
accuracy only if the measurement is within its range.

Construct a table to record your measurements in the space below.

Complete the following questions to show your understanding of forces.
1. (a)
What is the unit of force and what is its symbol? …………………………………
(b)
Name three types of forces that can act over a distance rather than by contact.
………………………………………………………………………………………….
2. You are sitting on a chair.
(a) What are the two balanced forces that are acting on you?
…………………………………………………………………………………………….
(b) What would happen if these forces were not balanced?
…………………………………………………………………………………………….
…………………………………………………………………………………………….
3. Imagine you are abseiling down a cliff. What are the two forces acting on you? How
would you know if they are balanced or not?
…………………………………………………………………………………………………
…………………………………………………………………………………………………
4. Complete the table below. For the last column, choose from the list below:
starting an object moving/slowing down an object that is moving
balancing another force, and preventing movement
changing the direction of movement
bending an object
SITUATION
OBJECT ON WHICH
FORCE ACTS
ball
WHAT THE FORCE IS
DOING
ACTIVITY 2: SCIENTIFIC EYE (Forces & Friction Videos)

Watch “Push and pull forces” and “Friction: videos on Clickview.
1.
What sorts of forces are there?
........................................................................................................................................
2.
What do all forces do?
........................................................................................................................................
3.
Which force pulls you down? ……………………………………………………………….
4.
What is ‘air resistance’?
........................................................................................................................................
5.
What forces act when someone jumps on a trampoline?
........................................................................................................................................
........................................................................................................................................
6.
Give an example of something needing a pull and a lift.
........................................................................................................................................
7.
Why are sea creatures streamlined?
........................................................................................................................................
8.
What is friction?
........................................................................................................................................
........................................................................................................................................
9.
How can friction be useful?
........................................................................................................................................
........................................................................................................................................
10. How can it be shown that friction produces heat?
........................................................................................................................................
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11. How can friction be reduced?
........................................................................................................................................
........................................................................................................................................
12. What practical examples of ‘useful’ friction are shown towards the end of the video?
........................................................................................................................................
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ACTIVITY 3: GRAVITY

1.
Watch the Brainpop “Gravity”
Look at the diagram opposite. Choose the
correct word to complete each sentence.
(a)
The force of gravity is a
…………………………… (push/pull).
(b)
A gravitational force pulls the spring
…………………………… (up/down).
(c)
The heavier the object, the
………………………..…..(less/greater)
the gravitational force.
(d)
The stronger the force, the ……………..…… (more/less) the spring stretches
(e)
A 10N weight is a ………………… (larger/smaller) force than a 20N weight.
(f)
A 20N forces stretches the spring ……………… (twice/half) as much as a 10N
force.
(g)
Complete the table below.
WEIGHT (N)
STRETCH (cm)
100
8
200
300
24
400
32
40
(h)
Predict how much a 50N weight would stretch the spring based on the table.
…………………………………………………………………………………………
2.
Imagine you are going on a trip to the planets. Your travel agent has given you this
table showing the force of gravity on each of the planets.
(a)
Where would you weigh the most? ………………………………………………..
What difference would this make to getting around the planet?
…………………………………………………………………………………………
(b)
Where would you be weightless? …………………………………………………
(c)
Suggest why the gravity is similar on Mercury and Mars.
…………………………………………………………………………………………
3.
(d)
On which planet would you need the least fuel for blast off? …………………..
(e)
How high can you jump on Earth? ...................................................................
(f)
How high would you be able to jump on the moon? …………………………….
Identify TWO toys for which gravity plays a role in their operation.
........................................................................................................................................
........................................................................................................................................
ACTIVITY 4: MAGNETIC FORCES

Carry out an investigation to find out which objects are attracted to a magnet..
1. Identify the objects that were attracted to the magnet. ………………………………...
…………………………………………………………………………………………………
…………………………………………………………………………………………………
2. Are all metals attracted to magnets? Give a reason to support your answer.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
3. Of the materials attracted to the magnet, which one was attracted the most?
…………………………………………………………………………………………………
4. Which materials seemed able to ‘block’ the magnetic force?
…………………………………………………………………………………………………

Hold different poles of two bar magnets together.
Record whether the magnets attract or repel in each case.
…………………………..
…………………………..
…………………………..
…………………………...
Complete the following sentence to summarise your findings.
Like poles …………………….. but unlike poles ………………………

Identify any toys that you have ever played with that contained something magnetic.
……………………………………………………………………………………………………...
……………………………………………………………………………………………………...

Record how you might be able to get one magnet to ‘float’ above another in a test tube.
Explain how this behaviour in terms of gravitational and magnetic forces.
……………………………………………………………………………………………………...
……………………………………………………………………………………………………...
……………………………………………………………………………………………………...
……………………………………………………………………………………………………...
Collect a bar magnet and a horseshoe magnet and a box of paperclips or pins. Hold
one of the magnets above the paperclips or pins and lower it slowly. Lift it up and
observe where the paperclips or pins are attached. Repeat with the other magnet.
1. Which parts of the bar magnet hold the most paperclips?
………………………………………………………………………………………………
2. Which parts of the bar magnet hold the least number of paperclips?
………………………………………………………………………………………………
3. Write an inference to explain your observations.
………………………………………………………………………………………………
………………………………………………………………………………………………
4.
Complete the sentences below.
(a)
A substance which is attracted to a magnet is said to be ………………………
(b)
A magnet can exert a ……………. on a piece of iron without touching it.
(c)
Magnets can be made of ………………….. or ………………. or ………………
(d)
All magnets have two ……………………..
(e)
One end of the magnet is called the ……………………………… The other end
is called the ………………………………
(f)
Two south poles or two north poles are called …………………….. poles
(g)
When two magnets push each other apart we say they ………………………
(h)
Like poles …………………… and …………………. poles attract.
5.
An electrician has a magnetised screwdriver to help her hold screws. Which of the
following will the screwdriver attract: steel screws, brass screws, aluminium washers,
steel washers, copper wire?
………….……………………………………………………………………………………….
………….……………………………………………………………………………………….
6.
Use the words magnetic and non-magnetic to explain how you can separate a mixture
of small pieces of iron and copper (known as iron filings and copper turnings).
………….……………………………………………………………………………………….
………….……………………………………………………………………………………….
………….……………………………………………………………………………………….
7.
The magnetic couplings in the Lego train below are either blue or red.
They will link up only if you join a red to a blue. Suggest a reason for this.
………….……………………………………………………………………………………….
………….……………………………………………………………………………………….
8. Is the bar magnet a permanent or a temporary magnet? Explain your answer.
………………………………………………………………………………………………
………………………………………………………………………………………………
ACTIVITY 5: MAGNETIC FIELDS

Carry out the investigation “Mapping the magnetic field”. Please ask your teacher about
the correct technique before you begin to ensure that no iron filings come into contact
with the bar magnet. Record results below.
MAGNETIC FIELD OF BAR MAGNET
1. Where does the magnetic field appear to be the strongest? How do you know this?
…………………………………………………………………………………………….
…………………………………………………………………………………………….
2. What happens to the magnetic field as you get further away from a magnet?
…………………………………………………………………………………………….

Watch the BrainPop on magnetism

Answer the questions below to test your understanding of magnetic fields and forces.
1. What is a magnetic field? Can we see one? Explain your answer.
…………………………………………………………………………………………….
…………………………………………………………………………………………….
2. The diagram shows a magnet and its magnetic field. A-C are steel ball bearings.
(a) Which ball is most attracted? ………
(b) Which ball is least attracted? ………
(c) Rank the positions A-C in order of
strongest to weakest magnetic field.
…………………………………………
ACTIVITY 6: ELECTRICITY AND MAGNETS

Carry out an investigation to make an electromagnet.
RESULTS:
Voltage of power supply
(V)
2
Number of turns of wire
2
20
2
25
2
30
4
15
4
20
4
25
4
30
Number of paperclips
picked up
15
1. What effect does increasing the number of turns of wire have?
………………………………………………………………………………………………
………………………………………………………………………………………………
2. What is the effect of increasing the voltage?
………………………………………………………………………………………………
………………………………………………………………………………………………
3. Explain why an electromagnet is called a ‘temporary magnet’.
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
4. Describe TWO ways to reverse the poles of your electromagnet.
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
5.
Arianna made her own electromagnet to find out how the number of windings around a
nail affected the number of paperclips that the nail could pick up. She used the circuit
shown in Investigation 6.10 with the power supply set to 2 volts. Arianna then repeated
her measurements with the power supply set to 4 volts and 6 volts. She recorded her
observations in a table and used it to construct the graph shown below.
(a) How many paperclips did Arianna lift with 20 windings and 6 volt power supply?
………………………………………………………………………………………………
(b)
Arianna lifted 12 paperclips when the power supply was set to 4 volts. How many
windings were there around the nail at this time?
………………………………………………………………………………………………
(c)
How many paperclips could Arianna expect to lift with 50 windings around the nail
and the power supply set to 2 volts?
………………………………………………………………………………………………
(d)
Suggest a way that Arianna would be able to improve the reliability of her results.
………………………………………………………………………………………………

Watch the BrainPop on electromagnets
Identify THREE differences between electromagnets and regular magnets.
…………………………………………………………………………………………………….
…………………………………………………………………………………………………….
…………………………………………………………………………………………………….

1.
Complete the following passage to show your understanding of electromagnets.
(a)
When an electric ………………………….. flows through a wire, the wire has a
magnetic field around it.
(b)
An …………………………………. is a temporary magnet made from a coil of
wire (………………………..) wound round a piece of iron. The electromagnet
creates a magnetic field when electricity passes through the coil.
(c)
An electromagnet is similar to a …………………………. magnet, but it can be
turned on and off by turning the electricity on and off.
2.
Describe THREE uses of electromagnets.
………………………………………………………………………………………………..
………………………………………………………………………………………………..
………………………………………………………………………………………………..
………………………………………………………………………………………………..
………………………………………………………………………………………………..
………………………………………………………………………………………………..
3.
Leanne wants to find out whether her electromagnet is as strong as Scott’s. To do
this she counts how many paperclips each electromagnet will pick up. She repeats
her measurement three times for each electromagnet. Her results are as follows:
(a)
Which electromagnet is stronger – Leanne’s or Scott’s? ……………………….
(b)
Would the result have been the same if Leanne had tested each
electromagnet only once? Explain.
…………………………………………………………………………………………
…………………………………………………………………………………………
…………………………………………………………………………………………
4.
The diagram below shows a musical doorbell.
(a)
Explain how the doorbell works.
……………………………………………………………………………………….
……………………………………………………………………………………….
……………………………………………………………………………………….
……………………………………………………………………………………….
……………………………………………………………………………………….
……………………………………………………………………………………….
(b)
When the switch is pressed and then released, would the bell go ‘ding-dong’ or
‘dong-ding’? Give a reason for your answer.
……………………………………………………………………………………….
……………………………………………………………………………………….
……………………………………………………………………………………….
ACTIVITY 7:
ATOMS & ELECTRICAL CHARGE
Matter (anything with mass) is composed of tiny particles called atoms. Atoms are far too
small to be viewed with the naked eye, but there is a lot of scientific evidence which suggests
they exist. Atoms are themselves composed of small particles that are known as subatomic
particles. The three basic types of subatomic particle are protons, electrons and neutrons.
The protons and neutrons are located in the central core of the atom, called the nucleus and
the electrons orbit the nucleus as shown above. The protons have a positive charge, the
electrons have a negative charge and the neutrons have no charge.
The materials we see and touch in our everyday lives do not carry an overall charge. It is
safe to pick objects up without fear of being ‘zapped’. This is because the atoms which make
up the objects carry no overall charge because they have the same number of positive
charges (protons) and negative charges (electrons). We say they are electrically neutral.
In a previous activity, you rubbed a plastic pen and it attracted pieces of paper because it
was charged. Similarly, you can rub a balloon or plastic ruler on wool to attract water or hair.

Carry out a static electricity investigation
1. Describe the movement of the single balloon. ……………………………………………
2. Does the rubbed balloon have the same charge as the woollen cloth? Explain.
………………………………………………………………………………………………….
………………………………………………………………………………………………….
3. Describe the movement of the two balloons. ……………………………………………..
4. Do the rubbed balloons have like or unlike charges? Explain.
………………………………………………………………………………………………….
………………………………………………………………………………………………….
5. Complete the sentence: Object with like charges …………………. each other and
objects with unlike charges ……………………. each other.

Watch the BrainPop on static electricity
Whilst it is difficult to change the number of protons in atoms (because they are contained in
the nucleus of the atom), it is relatively easy to change the number of electrons in some
objects. This is exactly what we are doing when we rub rods or other plastic materials with
material such as wool or silk. Two specific examples are described below”
e.g. When a perspex rod is rubbed with silk, the rubbing removes some electrons from some
of the atoms making up the perspex. These electrons are transferred to the silk cloth.
1.
What charge will a perspex rod carry after it has been rubbed by silk? …………………...
2.
What about the charge on a silk cloth? …………………….
When an ebonite rod is rubbed with wool, the opposite happens. This time, electrons are
removed from atoms in the woollen cloth and are transferred to the ebonite rod.
3.
What charge will the ebonite rod carry after it has been rubbed by the wool? ……………
4.
What about the woollen cloth? …………………….
These two situations (i.e. ‘charging’ an object) are described in the diagrams below:
The only way
to charge an
object is to
add or remove
electrons!
silk cloth

Carry out The Van de Graaff generator” investigation
PART A
Once the Van de Graaff generator has become …………………., placing the rod near
the dome causes a ………………..….. which causes it the dome to …………………..
PART B
1. What happens to the wool? ………………………………………………………………..
2. Explain why this happens in terms of the charges on the dome and on the wool.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
3. The wool forms a pattern around the dome. Suggest what this pattern might show.
…………………………………………………………………………………………………
ACTIVITY 8: MORE ON STATIC ELECTRICITY

Carry out a “defying gravity” investigation
1. Explain the behaviour of the water and balloon in your own words.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
…………………………………………………………………………………………………
2. Explain the effect of the cloth on the balloon.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
3. The two particles of an atom that carry electric charge are the ………………………..
(with a positive charge) and the …………………………. (with a negative charge).
4. A plastic ruler becomes negatively charged when it is rubbed with a woollen cloth.
(a) Describe what has happened to the cloth and ruler at a subatomic level.
……………………………………………………………………………………………...
……………………………………………………………………………………………...
(b) As the ruler becomes negatively charged, the cloth becomes ……………………...
charged because it now has fewer electrons than ……………………….
5. Two positively charged objects would be expected to …………………….. each other.
Two negatively charged objects would be expected to …………………... each other.
Oppositely charged object would be expected to ……………………… each other.
6. Explain using a diagram how a neutral object gets attracted to a charged object.
7. What is term used to describe the release of built up charge? …………………………
8. Two balloons are hanging on threads next to each other, but not touching. They
begin to move away from each other. If one of the balloons is positively charged,
identify the charge of the other balloon.
………………………………………………………………………………………………….
9. Explain why the student touching the dome of a Van de Graaff generator would be
wearing rubber soled shoes and standing on a plastic mat.
………………………………………………………………………………………………….
………………………………………………………………………………………………….
………………………………………………………………………………………………….
10. Use the following list of observations to determine whether balloons A, B, C and D
are positively or negatively charged. Balloon E is known to be positively charged.
 Balloon A is attracted to balloon B.
 Balloon D is attracted to balloon E.
 Balloon C repels balloon A.
 Balloon B repels balloon D.
………………………………………………………………………………………………….
11. If a pen is rubbed with a woollen cloth, it can attract a small piece of paper.
(a) Is the pen neutral or charged? …………………………………
(b) Is the small piece of paper neutral or charged? ………………………………….

Complete the following table to compare electrostatic forces and magnetic forces.
electrostatic forces
similarities
differences
magnetic forces