Heating and Cooling

Question 1

What is the change of state called when a gas turns into a liquid?

Answer 1

Condensing

Question 2

What is the change of state called when a liquid turns into a solid?

Answer 2

Freezing

Question 3

What is the change of state called when a liquid turns into a gas?

Answer 3

Boiling

Question 4

What is the change of state called when a solid turns into a liquid?

Answer 4

Melting

Question 5

What is temperature?

Answer 5

Temperature is a measure of how hot or cold a substance is, measured in degrees Celsius, °C.

Question 6

What is heat?

Answer 6

Heat is a measure of the amount of energy contained in an object’s thermal energy store, measured in joules, J.

Question 7

What is thermal energy?

Answer 7

Energy stored in heated objects

Question 8

What is the direction of movement of energy between two objects of different temperatures?

Answer 8

Hot to cold

Question 9

Which statement is true?

1. Energy transfers from the hotter to the cooler object.
2. Energy transfers from the cooler to the hotter object.

Answer 9

1. Energy transfers from the hotter to the cooler object.

Question 10

How long will the transfer of energy between two objects or areas at different temperatures continue for?

Answer 10

Until both objects are at the same temperature.

Question 11

What is the law of conservation of energy?

Answer 11

Energy cannot be created or destroyed, only transferred or stored.

Question 12

What causes an object to have energy in its thermal energy store?

Answer 12

The vibration or movement of its particles.

Question 13

What happens when particles gain more energy?

Answer 13

The particles vibrates more.

Question 14

In the example shown, what factor affects the amount of energy contained in the object’s thermal energy store?

Answer 14

Its temperature.

Question 15

In the example shown, what factor affects the amount of energy contained in the object’s thermal energy store?

Answer 15

Its mass.

Question 16

Solids transfer energy by ___________

Answer 16

Conduction

Question 17

Fluids (liquids and gases) transfer heat by ___________

Answer 17

Convection

Question 18

Which method of heat transfer causes heat to be transferred to the air above a cup of hot tea?

Answer 18

Convection

Question 19

A solid is a material with particles . . .

Answer 19

that vibrate around fixed positions.

Question 20

What is a thermal conductor?

Answer 20

A substance that transfers energy by conduction quickly.

Question 21

What is a thermal insulator?

Answer 21

A substance that transfers energy by conduction slowly or not at all.

Question 22

A material that is a poor thermal conductor is called a __________________

Answer 22

thermal insulator.

Question 23

In what situation does conduction occur?

1. in the absence of particles
2. in substances with touching particles
3. in fluids

Answer 23

2. in substances with touching particles

Question 24

What happens to the particles in a substance as it’s being heated?

1. They gain energy and vibrate more.
2. They gain energy and start to vibrate.

Answer 24

1. They gain energy and vibrate more.

Question 25

What effect does heating a particle in one part of a substance have on the nearby particles?

Answer 25

The heated particles collide with nearby particles, causing them to vibrate more as well.

Question 26

Describe the stages of energy transfer by conduction:

Answer 26

1. Particles that are heated gain energy.
2. The increase in energy causes the particles to vibrate more.
3. The particles that are vibrating more collide into the particles around them, transferring the energy.
4. The movement of energy through a solid is called conduction.

Question 27

Describe how conduction occurs through a metal rod that is being heated by a Bunsen burner:

Answer 27

1. The Bunsen burner flame heats the metal rod.
2. As they are heated, the particles in the rod gain energy and vibrate more.
3. The heated particles collide with nearby particles, causing them to also vibrate more.
4. As more and more particles vibrate, there are more and more collisions, so energy transfer continues throughout the metal rod.
5. Eventually the temperature of the whole rod increases.

Question 28

Why is conduction very slow in liquids?

Answer 28

The particles are loosely packed, so they don’t collide often.

Question 29

Why doesn’t conduction occur in a vacuum?

Answer 29

There are no particles in a vacuum.

Question 30

How is energy transferred through a solid?

Answer 30

By conduction

Question 31

Why does conduction rarely happen in gases?

Answer 31

The particles are spread out, so the particles rarely collide.