# Exploring Magnetism

In this worksheet, students will explain how materials can be made magnetic and how they can be demagnetised, which means how magnetism can be removed.

Key stage:  KS 3

Curriculum topic:   Physics: Electricity and Electromagnetism

Curriculum subtopic:   Magnetism

Difficulty level:

### QUESTION 1 of 10

Soft magnetic materials - like soft iron - can be turned into weak magnets when you place a strong, permanent magnet near them. Steel can also be magnetised (not as easily as iron) but it can stay magnetised longer. You can magnetise a steel rod if you stroke it with a permanent magnet several times in the same direction. You can also place a steel bar in a magnetic field, then heat it to a high temperature and hammer it as it cools. A piece of iron or steel could be magnetised by placing it in a coil of wire with an electric current passing through it, always in the same direction.

Some materials - like iron, cobalt or nickel - have little groups of atoms in them that behave like magnets. These groups of atoms are called magnetic domains. In unmagnetised materials, the magnetic domains are arranged randomly and point in different directions, cancelling each other out. In magnetised materials, the domains are aligned in such a way that they all point in the same direction. The better the alignment is, the stronger the magnet.

The diagram below shows the alignment before and after magnetising a piece of metal:

The reason an unmagnetised nail is attracted to a magnetic piece of iron is that more domains in the nail line up when it is placed near the magnet. When the magnet is removed, most domains return to a random arrangement and the nail becomes demagnetised.

In non-magnetic materials the domains remain in a random arrangement, even when placed in a magnetic field.

Magnetism can also be removed in a number of ways:

• Drop or hammer the magnet; this reduces the alignment and the magnetism
• Heat the magnet
• Stroke one magnet with another in different directions. This works better for demagnetising weaker magnets.

Which of the options below is a soft magnetic material?

plastic

soft iron

soft cotton

How can you magnetise a steel rod?

You can stroke it with a magnet in a random fashion.

You can cool it and then hammer it.

You can put it in the fridge.

You can stroke it with a magnet several times in the same direction.

Select two types of energy that help create magnetism.

electricity

thermal (heat)

kinetic

gravitational potential

In the answer box below, write the word which completes this sentence:

A magnetic domain is a small group of ________ that behave as tiny magnets.

Select the option which completes this sentence:

In a magnetised material, ...........

all domains point to the same direction.

domains point to different directions.

domains change the direction they point to quickly.

there are no domains.

Iron, nickel and cobalt can all be:

magnetic

soft

solenoids

domains

Complete the following sentence by selecting two boxes below:

When a nail is unmagnetised, ........

the domains are aligned.

the domains are not aligned.

the domains point south.

How can you turn a non-magnetic material into a magnet?

You can place it within a magnetic field.

You can stroke it with a magnet.

You can heat it and then hammer it as it cools.

You cannot turn a non-magnetic material into a magnet.

Why does dropping a magnet reduce its strength?

it breaks

it heats up

the alignment of the domains is reduced

the domains point to the same direction

Select all of the correct ways of demagnetising a material (there are three correct options).

heat it

drop it or hammer it

stroke it with another magnet in the same direction

stroke it with another magnet in a random fashion

• Question 1

Which of the options below is a soft magnetic material?

soft iron
EDDIE SAYS
Various metals are magnetic materials.
• Question 2

How can you magnetise a steel rod?

You can stroke it with a magnet several times in the same direction.
EDDIE SAYS
By stroking it with a magnet several times in the same direction, the domains point to the same direction, which makes the material magnetic.
• Question 3

Select two types of energy that help create magnetism.

electricity
thermal (heat)
EDDIE SAYS
You can heat a magnetic material and then hammer it as it cools, or place it within an electric current and it acts as a magnet.
• Question 4

In the answer box below, write the word which completes this sentence:

A magnetic domain is a small group of ________ that behave as tiny magnets.

atoms
EDDIE SAYS
All matter is made of atoms.
• Question 5

Select the option which completes this sentence:

In a magnetised material, ...........

all domains point to the same direction.
EDDIE SAYS
Whether a material is magnetic or not depends on the direction of the domains.
• Question 6

Iron, nickel and cobalt can all be:

magnetic
EDDIE SAYS
These three metals can all be magnetic.
• Question 7

Complete the following sentence by selecting two boxes below:

When a nail is unmagnetised, ........

the domains are not aligned.
EDDIE SAYS
Magnetism depends on the direction of the domains. If they do not point to the same direction, then the material is not magnetic.
• Question 8

How can you turn a non-magnetic material into a magnet?

You cannot turn a non-magnetic material into a magnet.
EDDIE SAYS
Only certain materials can become magnetic.
• Question 9

Why does dropping a magnet reduce its strength?

the alignment of the domains is reduced
EDDIE SAYS
Whether a material is magnetic or not depends on the alignment of the domains.
• Question 10

Select all of the correct ways of demagnetising a material (there are three correct options).

heat it
drop it or hammer it
stroke it with another magnet in a random fashion
EDDIE SAYS
The focus is on reducing the alignment of the domains.
---- OR ----

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