Energy Transfer

Question 1

How can heat be transferred from place to place?

Answer 1

Conduction, Convection and Radiation

Question 2

Which kind of surfaces are better at absorbing light?

Answer 2

Dark, matt surfaces are better at absorbing heat energy than light, shiny surfaces.

Question 3

What does it mean to emit energy?

Answer 3

Give out energy.

Question 4

What does it mean to absorb energy?

Answer 4

Take in energy.

Question 5

What is another name for thermal radiation?

Answer 5

Infrared radiation.

Question 6

What happens as an object gets hotter?

Answer 6

It emits more infrared radiation.

Question 7

What type of radiation is infrared radiation?

Answer 7

Electromagnetic

Question 8

How is radiation different to conduction and convection?

Answer 8

It can pass through the vacuum of space.

Question 9

What does the kinetic particle theory explain?

Answer 9

The kinetic particle theory explains the properties of the different states of matter.

Question 10

Explain the arrangement and movement of particles in solids.

Answer 10

They are close together and have a regular pattern. They vibrate about in a fixed position.

Question 11

Explain the arrangement and movement of particles in liquids.

Answer 11

They are close together and are randomly spaced. They move around each other.

Question 12

Explain the arrangement and movement of particles in gas.

Answer 12

They are far apart and randomly spread. They move quickly in any direction.

Question 13

Name some of the properties of solids and why they are like this.

Answer 13

They have a fixed shape and cannot flow. They are like this because the particles cannot move from place to place. They cannot be compressed or squashed. They are like this because the particles are squashed and have no space to move into.

Question 14

Name some of the properties of liquids and why they are like this.

Answer 14

They flow and take the shape of their container. They are like this because the particles move around each other. They cannot be compressed or squashed. They are like this because the particles are close together and have no space to move into.

Question 15

Name some of the properties of gases and why they are like this.

Answer 15

They flow and completely fill their container. They are like this because the particles can move quickly in all directions. They can be compressed or squashed. They are like this because the particles are far apart and have space to move into.

Question 16

How does heat energy move?

Answer 16

Conduction

Question 17

What is a poor conductor of heat?

Answer 17

An insulator

Question 18

What is the difference between non-metals, gases and metals?

Answer 18

Metals are good conductors of heat but non-metals and gases are usually poor conductors of heat.

Question 19

When does convection occur?

Answer 19

Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection.

Question 20

When do liquids and gases expand?

Answer 20

When they are heated. This is because the particles in liquids and gases move faster when they are hot as to when they are cold.

Question 21

What are evaporation and condensation?

Answer 21

Changes of state.

Question 22

What is evaporation?

Answer 22

Evaporation involves a liquid changing to a gas.

Question 23

What is condensation?

Answer 23

Condensation involves a gas changing to a liquid.

Question 24

When does the rate of condensation increase?

Answer 24

The rate of condensation increases if the temperature of the gas is decreased.

Question 25

When does the rate of evaporation increase?

Answer 25

The rate of evaporation increases if the temperature of the liquid is increased. It is also increased if: the surface area of the liquid is increased or if air is moving over the surface of the liquid.

Question 26

What are U - Values?

Answer 26

U-values measure the effectiveness of a material as an insulator in buildings.

Question 27

If a material has a high U - Value, is it a good heat insulator?

Answer 27

No. The lower the U-value is, the better the material is as a heat insulator.

Question 28

What is payback time?

Answer 28

The payback time of an energy-saving solution is a measure of how cost-effective it is. Here is the equation to calculate payback time: payback time (years) = cost of installation (£) ÷ savings per year in fuel costs (£) The payback time will be shortest if the cost of installation is low compared to the savings made each year.

Question 29

What is temperature?

Answer 29

A measure of how hot something is. It is measured in Degrees Celsius.

Question 30

What is heat?

Answer 30

A measure of the thermal energy contained in an object. It is measured in Joules.

Question 31

What is Specific Heat Capacity?

Answer 31

The specific heat capacity of a substance is the amount of energy needed to change the temperature of 1 kg of the substance by 1°C.

Question 32

Why does water have such a high Specific Heat Capacity?

Answer 32

Water has a particularly high specific heat capacity. This makes water useful for storing heat energy, and for transporting it around the home using central heating pipes.

Question 33

What is the equation for working out Specific Heat Capacity?

Answer 33

E = m × c × θ E is the energy transferred in joules, J m is the mass of the substances in kg c is the specific heat capacity in J / kg °C θ (‘theta’) is the temperature change in degrees Celsius, °C