Heat

Question 0

What happens when we heat a solid, liquid or gas?

Answer 0

It expands.

Question 1

Heat

Answer 1

Is a form of energy.

Question 2

What happens we cool a solid, liquid or gas?

Answer 2

It contracts.

Question 3

Heat transfer

Answer 3

> Heat is transferred by 3 methods:

     1. Convection.
     2. Conduction.
     3. Radiation.

Question 4

Conduction

Answer 4

Heat travels from particle to particle along a substance, normally a solid.

Question 5

Convection

Answer 5

Heat travels through a fluid (liquid or gas) when the particle move and carry the heat.

Question 6

Radiation

Answer 6

Heat travels from a hot object without the need for a medium, does not need a solid, liquid or gas to go through, will flow through a vacuum.

Question 7

Conductor

Answer 7

Something that allows energy, eg. Heat, to flow through it. Eg. metal is a good conductor.

Question 8

Insulators

Answer 8

An insulator is a substance that won’t allow heat to flow through it easily, eg. plastic.

Question 9

To show that a solid expands when heated and contracts when cooled

Answer 9

Ball and ring apparatus.

Question 10

Water

Answer 10

Water begins to expand when cooled below 4°C

Question 11

Air

Answer 11

Is a good insulator, keeps animals warm, air is trapped by the fur and helps to insulate the animal.

Question 12

Layers

Answer 12

The hairs on our arms are not very good at keeping us warm, if we wear layers of clothes air is trapped to keep us warm.

Question 13

Winds are formed by convection

Answer 13

The sun heats the Earth. This causes hot air to rise. As hot air rises it cools and then sinks down to the ground. The movement of the air is called Wind/Air currents. Air currents are sometimes called convection currents

Question 14

Temperature

Answer 14

A messure of how hot an object is.

Question 15

What is the temperature of the sun?

Answer 15

6000°C

Question 16

Thermometer

Answer 16

The liquid in the thermometer will expand and rise when heated and will contract and fall when cooled.

Question 17

Water boiling point

Answer 17

100°C

Question 18

Water freezing point

Answer 18

0°C and lower

Question 19

Melting point

Answer 19

When a solid turns to a liquid.

Question 20

Boiling point

Answer 20

When a liquid turns to gas.

Question 21

Freezing point

Answer 21

When a liquid turns to a solid.

Question 22

Condensation

Answer 22

Is a gas turning into a liquid.

Question 23

Evaporation

Answer 23

When a liquid turns to a gas.

Question 24

Pressure and Boiling Point

A kettle will normally boil at 100°C, but will boil at 70° on top of Mt. Everest.

Answer 24

Atmospheric pressure is less so it is easier for the water vapour to escape.

Question 25

Latent heat

Answer 25

The heat taken in or given out when a substance is changing state without a change in temperature.

Question 26

Graph pg330 into hardback copy.

Answer 26

• When a solid changes to a liquid, latent heat of fusion is used.
• When a liquid changes to a gas, latent heat of vaporisation is used.

Question 27

Dull, Black surface radiates…

Answer 27

…heat better than a shiny surface.

Question 28

Dull, Black surface absorbs…

Answer 28

…Heat better than a shiny surface.

Question 29

When water is below 4°C…

Answer 29

…it begins to expand.

Question 30

The amount of heat in a substance depends on…

Answer 30

…temperature, mass and what it is made of, e.g. 200ml of water at 60°C has twice as much heat as 100ml of water at 60°C.