Conduction and Insulation Worksheet

Conductors let energy flow through them (for example, electrical or thermal energy). Heat energy travels through solids because of conduction. Materials that do not conduct heat well are heat insulators. We use these to insulate houses and prevent loss of heat energy.

Metals are good heat conductors. Wood and plastic are good heat insulators.

Wall insulation

Solids are better heat conductors than liquids and gases. When solids are heated their particles gain energy and vibrate more; they also need more space to move around. The particles collide with (bump into) each other and pass the energy on.

Liquids and gases are better insulators than solids, because their particles are far apart.

What is a heat conductor?

A material that lets thermal energy flow through it.

A material that does not let thermal energy flow through it.

A material that lets electrical energy flow through it.

A material that does not let electrical energy flow through it.

Cavity wall insulation

What is an insulator?

One of the heating ducts in a car engine.

A special tube that is used to heat the bath.

A material that does not let energy flow through it.

A material that lets energy flow through it.

How can you tell whether something is a good heat conductor or insulator?

Good heat conductors feel cold and heat insulators can give you an electric shock.

Good heat conductors feel warm and heat insulators feel cold.

Good heat conductors are brown and heat insulators are white.

Good heat conductors feel cold and heat insulators feel warm.

Why do good heat conductors feel hot/cold (depending on your answer for Question 3)?

They conduct heat away from you quickly.

They trap the heat inside them.

They let the heat escape into the environment.

They were not warmed up before use.

Winter jacket

Bird feathers trap air inside them. Why do we use bird feathers in duvets and jackets?

Air trapped in them does not insulate heat.

Air trapped in them does not conduct electricity.

Air trapped in them is warm.

Air trapped in them does not conduct heat.

What model helps us explain conduction and insulation?

The particle model of solids.

The particle model of matter.

A model of atomic structure.

A model of heat flow.

Diagram of solid conducting heat

Why are solids better heat conductors?

Their particles are further away from each other, so it is easy for energy to be passed on.

Solids have fewer particles.

Their particles are very close together, so it is easy for energy to be passed on.

Their particles are very close together, so it is difficult for energy to be passed on.

Model for solid, liquid and gas

Why are gases very poor heat conductors?

Their particles are far away from each other, so heat cannot be passed on.

Their particles are far away from each other, so heat can be passed on.

Their particles are close to each other, so heat cannot be passed on.

Their particles are close to each other, so heat can be passed on.

What happens to particles in solids when they are heated up?

They gain energy and vibrate more slowly.

They gain energy and vibrate faster.

They lose energy and vibrate faster.

They lose energy and vibrate more slowly.

Why do metals expand (get bigger) when they are heated up?

Their particles need less space to move, because they vibrate more slowly.

Their particles need less space to move, because they vibrate faster.

Their particles need more space to move, because they vibrate more slowly.

Their particles need more space to move, because they vibrate faster.

ANSWERS

Question 1

What is a heat conductor?

CORRECT ANSWER

A material that lets thermal energy flow through it.

EDDIE SAYS

Conductors let energy flow through them, but insulators do not. Here it's HEAT energy, so that's a thermal conductor, like all metals.

ANSWERS

Question 2

Cavity wall insulation

What is an insulator?

CORRECT ANSWER

A material that does not let energy flow through it.

EDDIE SAYS

Conductors let energy flow through them, but insulators do not.

ANSWERS

Question 3

How can you tell whether something is a good heat conductor or insulator?

CORRECT ANSWER

Good heat conductors feel cold and heat insulators feel warm.

EDDIE SAYS

If you walk around bare foot, tiles feel colder than carpets. Tiles conduct heat away from you fast, so your feet feel cold.

ANSWERS

Question 4

Why do good heat conductors feel hot/cold (depending on your answer for Question 3)?

CORRECT ANSWER

They conduct heat away from you quickly.

EDDIE SAYS

If you walk around bare foot, tiles feel colder than carpets. Tiles conduct heat away from you fast, so your feet feel cold.

ANSWERS

Question 5

Winter jacket

Bird feathers trap air inside them. Why do we use bird feathers in duvets and jackets?

CORRECT ANSWER

Air trapped in them does not conduct heat.

EDDIE SAYS

Insulators trap air in them. Air particles are not close to each other, so the energy cannot be transferred easily.

ANSWERS

Question 6

What model helps us explain conduction and insulation?

CORRECT ANSWER

The particle model of matter.

EDDIE SAYS

All matter is made of particles. The arrangement of particles in solids, liquids and gases is different and helps to explain why some solids conduct thermal energy better than liquids or gases (their particles are close and so transfer the energy faster).

ANSWERS

Question 7

Diagram of solid conducting heat

Why are solids better heat conductors?

CORRECT ANSWER

Their particles are very close together, so it is easy for energy to be passed on.

EDDIE SAYS

For heat to be transferred you need things in contact with each other, like the particles in solids.

ANSWERS

Question 8

Model for solid, liquid and gas

Why are gases very poor heat conductors?

CORRECT ANSWER

Their particles are far away from each other, so heat cannot be passed on.

EDDIE SAYS

For a substance to be a gas, its particles must be far apart, moving fast with a lot of energy. That means that they are very poor at transferring thermal energy as heat conduction requires the energy to be passed from particle to particle.

ANSWERS

Question 9

What happens to particles in solids when they are heated up?

CORRECT ANSWER

They gain energy and vibrate faster.

EDDIE SAYS

Particles in solids do not move around like in liquids and gases; they only vibrate.

ANSWERS

Question 10

Why do metals expand (get bigger) when they are heated up?

CORRECT ANSWER

Their particles need more space to move, because they vibrate faster.

EDDIE SAYS

As the material gets hotter, it gains thermal energy so the particles it is composed of vibrate faster and further and so take up more space. When the solid cools down again, it contracts (gets smaller).