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Summary Sheets
8J
Magnets and electromagnets
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Magnetism is a non-contact force. Magnets attract magnetic materials. Iron, nickel
and cobalt are magnetic materials. Mixtures, like steel, that include a magnetic
material will also be attracted to a magnet. Other metals, like aluminium, are not
magnetic and will not be attracted to a magnet. Iron oxide is a compound that is a
magnetic material. It is used to make video and music cassettes and computer discs.
Magnetic materials can also block magnetism.
You can make a magnet from a piece of iron or steel.
Always stroke in the
same direction.
magnet
magnetic material
●
●
●
●
The two ends of a bar magnet are called the north seeking pole and the south
seeking pole or north pole and south pole for short.
A north pole and a south pole attract each other.
Two north poles or two south poles will repel each other.
The space around a magnet where it has an effect is called its magnetic field.
S
N
This is the shape of the magnetic field of a bar magnet.
You can find the shape of the magnetic field using iron filings or using a plotting
compass.
The Earth has a magnetic field. A compass is a small magnet that always points
north. But magnetic materials placed near a compass can change the direction that it
points.
Magnets can be used to sort iron and aluminium cans for recycling. Only the iron cans
are attracted to the magnet. Magnets can also be used for holding fridge doors shut,
and in compasses that sailors or walkers use.
A wire with electricity flowing through it has a magnetic field around it. An
electromagnet is a coil of wire with an electric current flowing through it.
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Summary Sheets (continued)
You can make an electromagnet stronger by:
●
●
●
increasing the number of coils of wire
increasing the size of the current (by increasing the voltage)
using an iron core.
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Electromagnets can be used for lifting things. They are also used in electric bells,
relays and in video and music recording.
Electromagnets are used to make bells work.
cell
pivot
springy metal
electromagnet
contact
gong
armature
A reed switch has two thin pieces of iron inside it. If a magnet is held near the
switch, the pieces of iron are magnetised and touch each other. A reed switch can also
be switched on using an electromagnet. Any switch that is worked by electricity is
called a relay.
Relays are used to make things safer. For example, the starter motor in a car uses a
high current and needs thick wires for the current to flow through. A relay is used in
a car so that the driver does not have to touch any part of the circuit that has a high
current.
circuit 1
When current flows in
circuit 1 the coil becomes
an electromagnet.
contacts
iron armature
circuit 2
coil of wire
When the armature moves
the iron connects the two
contacts and electricity can
flow in circuit 2.
The iron armature
is attracted by the
electromagnet.
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Target Sheet
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Name
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Topic
8Ja
8Jb
8Jc
8Jd
8Je
Class
1
Target
Know which materials are magnetic.
2
Know some properties of magnetic
materials.
3
Know which materials will block
magnetism.
4
Know the rules for magnets
attracting and repelling.
1
Know the names of the two ends of
a magnet.
2
Know which way a compass needle
points.
3
Know what magnetic compasses are
used for.
4
Know how to make a magnetic
compass.
1
Know what a magnetic field is.
2
Know the shape of a magnetic field
around a bar magnet.
3
Know the direction of a magnetic field.
4
Know about the Earth’s magnetic field.
1
Know what an electromagnet is.
2
Know how to make an
electromagnet stronger.
3
Know how an electric bell works.
4
Know why relays are used in car starter
motor circuits.
1
Know what causes a magnetic field
around a wire.
2
Know the shape of the magnetic field
around an electromagnet.
3
Know why a core can make an
electromagnet stronger.
4
Know the shape of the magnetic field
around a straight wire.
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Word Sheets
8J
Word sheets that include new words from the ‘Focus on:’ pages are available on the
Exploring Science website.
8
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8Ja – Magnetic attraction
Word
attract
Pronunciation
Meaning
Two things pulling towards each other.
cobalt
cO-balt
A metal that is a magnetic material.
iron
A metal that is a magnetic material.
magnet
Something that can attract magnetic materials.
magnetic materials
Materials that are attracted to a magnet; iron, cobalt, nickel and steel are all magnetic
materials.
magnetism
A non-contact force.
nickel
A metal that is a magnetic material.
north pole
One end of a magnet. This ends points north if the magnet can move.
repel
Push away.
south pole
One end of a magnet.
steel
A mixture made mainly from iron; it is a magnetic material.
8Jb – Pointing north
Word
bar magnet
Pronunciation
Meaning
A straight magnet, shaped like a small bar.
compass
A magnetised piece of metal that can swing around – it points north.
north-seeking pole
The end of a magnet that points north if the magnet can move freely. Often just called
the north pole.
south-seeking pole
The end of a magnet that points south if the magnet can move freely. Often just called
the south pole.
8Jc – Force field
Word
iron filings
Pronunciation
f-eye-lings
Meaning
Tiny pieces of iron that are sometimes used to find the shape of a magnetic
field.
magnetic field
The space around a magnet where it can affect magnetic materials or other
magnets.
north magnetic pole
The place on the Earth where compasses point (it is not in the same place as
the North Pole marked on maps).
plotting compass
A small compass used for finding the direction of a magnetic field.
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Word Sheets (continued)
8Jd – Sounds magnetic/Keep your distance
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Word
armature
Pronunciation
Meaning
The iron part of a relay that moves when electricity is flowing in the solenoid
(or electromagnet).
electromagnet
A coil of wire with electricity flowing in it. An electromagnet has a magnetic
field like a bar magnet.
make and break
switch
The switch in an electric bell that opens and closes. It is operated by an
electromagnet that breaks the circuit whenever it is switched on.
permanent magnet
A magnet that keeps its magnetism – it does not depend on electricity.
reed switch
A switch made from two thin pieces of metal, which closes when it is in a
magnetic field.
relay
A switch that is switched on and off by electricity.
solenoid
A coil of wire.
8Je – Coils and cores
Word
core
Pronunciation
Meaning
A solid bar inside an electromagnet – usually made of iron.
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Summary Sheets
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Forces
Balanced forces are forces that are the same size but work in opposite directions. If forces are
balanced:
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• a stationary object stays stationary; • a moving object continues to move at the same speed.
A car or motorbike uses the energy stored in fuel to move at a steady speed because it needs a
force from the engine to balance the forces of air resistance and friction.
The amount of air resistance on something can be reduced by giving it a smooth, streamlined
shape. The air resistance increases as the speed increases, so cars use up more fuel per mile when
they are travelling fast. Air resistance is caused by air particles hitting the moving object. The
particles transfer energy to the object, which is why objects moving through air can get hot.
Pressure on solids
Pressure is the amount of force pushing on a certain area.
For a certain area, the bigger the force, the bigger the pressure. For a certain force, the bigger the
area, the smaller the pressure.
In this picture, the thumb is putting a force onto the head of the pin. The force is
transferred to the point of the pin. The point has a very small area, so there is a very
large pressure on the board, and the pin goes in.
In this picture, the thumb is putting a force directly on the board.
The area of the thumb is much larger than the area of the pin point, so there is only a
small pressure on the board. The thumb does not go into the board.
Sharp knife – a small area
giving a large pressure.
Snow shoes – a large area
giving a small pressure.
Magnets and electromagnets
Magnetism is a non-contact force. A magnet does not have to be touching something to attract
it. Magnets attract magnetic materials. Iron, nickel and cobalt are magnetic materials. Mixtures,
like steel, that include a magnetic material will also be attracted to a magnet. Other metals, such
as aluminium or copper, are not magnetic and will not be attracted to a magnet.
• The two ends of a bar magnet are called the north-seeking pole and the south-seeking pole,
or north pole and south pole for short.
• A north pole and a south pole attract each other.
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Summary Sheets (continued)
• Two north poles or two south poles repel each other.
A bar magnet is a permanent magnet, because it is always magnetic. A wire with electricity
flowing through it has a magnetic field around it. An electromagnet is a coil of wire with an
electric current flowing through it. It is only magnetic while the current is flowing.
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You can make an electromagnet stronger by:
• increasing the number of coils of wire
• increasing the size of the current (by increasing the voltage)
• using an iron core.
Magnetic fields
The space around a magnet where it has an effect is called its
magnetic field.
S
You can find the shape of the magnetic field using iron filings
or using a plotting compass.
The Earth has a magnetic field. A compass is a small magnet
that will point towards the Earth’s North pole. But magnetic
materials placed near a compass can change the direction that
the compass points towards.
N
This is the shape of the magnetic
field of a bar magnet. The magnetic
field of an electro magnet is a
similar shape.
Levers
Forces can be used to turn objects around pivots. A pivot is also
known as a fulcrum.
Levers work by magnifying the force that is put in (the effort) or
they can make the load move further than the effort. The amount
the force or distance is multiplied depends on the distances
between the load and the pivot and the effort and the pivot.
The hammer is acting as a
force multiplier.
force from hand
biceps muscle
effort
triceps
muscle
radius bone
pivot
The arm is acting as a distance multiplier.
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Level Ladder
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Name
Class
My Target Level is:
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Date
My final level is:
Tick the boxes that apply. Or use traffic lights to show how confident you are (red = ‘I don’t know
this’; orange = ‘I’m not very confident about this’; green = ‘I’m confident I know this’).
Level
At the end of the Unit:
I can do this This needs
more work
Working towards Level 4
Follow instructions and work safely during practical work.
Describe how magnets can affect magnets and other
materials.
Level 4
Recall what a magnetic field is, and that the Earth has one.
Describe how the features of different types of transport
make them suited for their purposes.
Appreciate some of the reasons why we depend on
transport.
Use iron filings to show the shape of a magnetic field.
Present data from investigations as bar charts.
Recall that electromagnets need electricity to stay
magnetised.
Level 5
Explain how pressure can be changed in a variety of
circumstances.
Describe some technological developments that have lead
to today’s forms of transport.
Estimate quantities to use in calculations.
Use a compass to plot the shape of a magnetic field.
Recall what drag is and the factors that affect it.
Recall how pressure depends on force and area, and some
ways in which pressure can be reduced or increased.
Describe how levers can be used.
Describe the shapes and directions of the magnetic fields
of bar magnets, electromagnets and combinations of
magnets.
Explain why compasses work.
Explain how simple levers work, and some of their uses.
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Level Ladder (continued)
8J
Level
At the end of the Unit:
I can do this This needs
more work
Level 6
Use the idea of particles to explain air resistance.
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Explain why a vehicle needs a force from the engine to keep
moving at a constant speed, and the effects of this on fuel
consumption and the need for streamlining.
Level 7
Link conclusions to scientific understanding.
Use graphs of my results to decide if two variables are
proportional or inversely proportional.
Evaluate the reliablity of evidence.
Describe the different classes of levers and how they can be
used.
Level 8
Use ideas about the Earth’s magnetic field to explain the
meanings of variation, dip and deviation.
Use ideas about domains to explain how to create and
destroy magnets.
Recall that the shape of the field around a current-carrying
wire is circular.
Recall the meaning of coefficient of drag and use it in
calculations.
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Word Sheets
8J
8Ja – Drag act
Word
Pronunciation
Meaning
air resistance
A force that tries to slow things down that are moving
through the air. It is a type of friction, and is also called
drag.
balanced forces
Two forces that are the same strength and working in
opposite directions.
drag
Air resistance and water resistance are both also called
drag.
streamlined
Something that has a smooth shape to reduce the air
resistance or water resistance.
water resistance
A force that tries to slow things down that are moving
through water. It is a type of friction, and is also called
drag.
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8Jb – Tracks and trains
Word
Pronunciation
Meaning
pascal
A unit for pressure. 1 Pa = 1 N/m2
pressure
A way of saying how spread out a force is.
8Jc – Floating trains
Word
Pronunciation
Meaning
attract
Pull towards.
bar magnet
A straight magnet shaped like a small bar.
cobalt
cO-balt
A metal that is a magnetic material.
core
A solid bar inside an electromagnet, usually made of iron.
electromagnet
A coil of wire with electricity flowing in it.
iron
A metal that is a magnetic material.
maglev
Trains that use electromagnets to make them float (or
levitate), above the tracks and move along are called
maglev trains.
magnet
Something that can attract magnetic materials.
magnetic material
Material that is attracted to a magnet; iron, cobalt, nickel
and steel are all magnetic materials.
magnetism
A non-contact force.
nickel
A metal that is a magnetic material.
non-contact force
A force, such as magnetism or gravity, that does not need
to be touching something to have an effect.
north pole
One end of a magnet. This end points north if the magnet
is free to move.
permanent magnet
A magnet that keeps its magnetism – it does not depend
on electricity.
repel
Push away.
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Word Sheets (continued)
8J
8Jc – Floating trains (continued)
Word
8
J
Pronunciation
Meaning
south pole
One end of a magnet. This end points south if the magnet
is free to move.
steel
A mixture made mainly from iron; it is a magnetic
material.
8Jd – Finding the way
Word
Pronunciation
Meaning
compass
A magnetised piece of metal that can swing around – it
points north.
magnetic field
The space around a magnet where it can affect magnetic
materials or other magnets.
north-seeking pole
The end of a magnet that points north if the magnet can
move freely. Often just called the north pole.
plotting compass
A small compass used for finding the direction of a
magnetic field.
south-seeking pole
The end of a magnet that points south if the magnet can
move freely. Often just called the south pole.
8Je – Change your attitude/What next for transport?
Word
Pronunciation
Meaning
ailerons
Flaps on the ends of an aeroplane’s wing, that help to
control it.
biceps muscle
The muscle on the front of the upper arm that makes the
arm bend.
distance multiplier
A lever where the load moves further than the effort.
effort
The force put on something, especially a lever.
force multiplier
A lever where the load is bigger than the effort.
fulcrum
A point about which something turns. Another name for a
pivot.
lever
A simple machine that can increase the size of a force, or
increase the distance the force moves.
load
The weight or force on something.
pivot
A point about which something turns. Another name for a
fulcrum.
radius bone
The bone between the elbow and wrist that the biceps
muscle pulls on.
sustainable
A way of living that does not use up non-renewable
resources or harm things in our surroundings. Something
that is sustainable allows things to continue into the
future.
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