Conductors and insulators

When engineers and designers are choosing
materials for household objects, cooking
utensils or household appliances, they need to
select the materials for those items carefully.

Why?

Some materials
allow heat to
pass through
them easily,
while others do
not. This is an
important thing
to consider,
especially for
tools and
appliances in the
kitchen.

What are conductors of heat?

Conduction is the way that heat travels
through objects, from an object that is hot
to an object that is cooler.

Materials that allow heat to pass through
them easily are known as good conductors
of heat.

Some metals are good conductors of heat.
Metals such as aluminium, steel, iron and
copper are good thermal conductors.

Why are good conductors
of heat useful?

Think of a metal
saucepan. We use a
saucepan to heat up or
cook the food inside it.
If the metal saucepan
was not good at
transferring the heat
from the stove to the
food inside the pan, the
food would never cook!

Do you enjoy toast?

If you put toast in the toaster and
press the lever down, you will see
the metal element going red or
orange after only a couple of
seconds. This glowing, yellow
colour shows the heating element
has gotten very hot!

This metal heating element
becomes hot very quickly
because metal is a very good
conductor of heat.

Can you think of any
other examples of good
conductors of heat?

?

?

?

?

? ?

?
?
?

Iron

Radiator

Kettle

Thermal Insulators

However, sometimes we do not want heat
to transfer from one object to another.

Materials that do not allow heat to
transfer through them are called thermal
insulators.

Why
might this
be useful?

Why might thermal
insulators be useful?

A good thermal insulator will
keep cold objects cold and hot
objects hot for a long time.

This can be important when the weather is
cold, to keep our houses warm or to keep
our tea warm when we go on a picnic!

Wood

What materials are
good insulators?

Plastic
Wool

Air is a good thermal insulator.

Air and other gases are not good
conductors of heat. That makes
them good insulators.

Think of a puffy ski jacket. It is filled with
down feathers, which trap warm air and
stops heat being lost from your body!

Can you
think of
any other
examples
of thermal
insulators
being used
in your
house or
school?

If you go up to your
attic, you might see
fluffy white/pink
insulation material
lining the roof
space. This works
like the ski suit.

The insulation traps warm
air and stops it being lost
from the house. This keeps
the house warm.

Everyday uses of thermal
insulators

Everyday uses of thermal
insulators

The handles on your
saucepans are usually made
of plastic or wood. This stops
the handle getting hot when
you are cooking.

Think of the toaster in the
picture. It has a plastic outer
cover. This stops it heating
up as the toaster gets hot.

Have you ever brought hot food or
drinks on a picnic. Usually we use
a thermos container or flask to
keep tea and other hot drinks hot.

Similarly, you might have a cooler box
for cold food when you go on a picnic.
Plastic is a good insulator and the
plastic box helps to keep the temperature
inside cool, because it doesn’t allow the
hot air from outside in.

Draw

Find the words that have something to do with conductors and insulators.

Multiple Choice

What is a conductor of heat?

• Materials that allow heat to pass through them easily.

• Materials that do not allow heat to transfer through them.

• Materials that do not allow light to pass through them.

• Materials that allow light to pass through them.

Multiple Choice

What is an insulator of heat?

• Materials that allow heat to pass through them easily.

• Materials that do not allow heat to transfer through them.

• Materials that do not allow sound to pass through them.

• Materials that do not allow sound to pass through them.

Match

Match the items on the list with a suitable material from the boxes below.

• spoon for cooking

• picnic cooler box

• pan

• the handle of a wok

• curtains

wood

plastic

steel

wood

cotton

• wood

• plastic

• steel

• wood

• cotton

Drag and Drop

Choose 3 examples of materials that conduct heat well​ ​

Placeholder

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Drag these tiles and drop them in the correct blank above

steel

iron

copper

wool

cotton

plastic

Reorder

Arrange the following metals based on their thermal conductivity from highest to lowest.

• copper

• aluminum

• zinc

• iron

1

2

3

4

• 1
• 2
• 3
• 4