Energy transfers

Question 1

Describe the energy transfers in your average power station.

Answer 1

• Non-renewable fuels like coal have CHEMICAL ENERGY
• When they are burnt in a huge furnace this is transferred to HEAT ENERGY
• This heat energy is used to boil water into steam which has KINETIC ENERGY and this is used to turn a turbine
• Turbine uses its kinetic energy to drive a generator which transfers the energy to ELECTRICAL ENERGY

Question 2

Describe the energy transfers in a nuclear fission reactor.

Answer 2

• When a nucleus splits it releases a lot of energy in the form of KINETIC ENERGY
• This is transferred to HEAT ENERGY in a heat exchanger
• The heat energy transfer itself to water and so the water is boiled and the steam has KINETIC ENERGY
• This energy is then used to turn a turbine which drives a generator, creating ELECTRICAL ENERGY

Question 3

Describe the energy transfers in a wind farm.

Answer 3

• KINETIC ENERGY from the wind transferred to ELECTRICAL ENERGY when it turns the propeller

Question 4

Describe the energy transfer in geothermal energy

Answer 4

• Cold water is pumped down into the earther crust when hot rocks transfer their HEAT ENERGY to the water, turning it to steam which has KINETIC ENERGY
• The steam drives a turbine, and then a generator, creating ELECTRICAL ENERGY

Question 5

Describe the energy transfers solar cells

Answer 5

• LIGHT ENERGY from the sun directly into ELECTRICAL ENERGY

Question 6

Describe the energy transfers in solar heating systems

Answer 6

• LIGHT ENERGY from the sun is converted to HEAT ENERGY as it heats up water in black pipes

Question 7

Describe the energy transfers in wave power

Answer 7

• KINETIC ENERGY from the movement of waves into ELECTRICAL ENERGY

Question 8

Describe the energy transfers in pumped storage

Answer 8

• Water is released from an upper reservoir at peak time.

- The KINETIC ENERGY from the falling water is converted into ELECTRICAL ENERGY by a turbine and generator

Question 9

How does fibre glasswool prevent energy loss by conduction and convection.

Answer 9

• The air spaces in fibres means that fibres are very bad conductors because the air particles are widely spaced so cannot transfer heat energy vibrations very well.
• Air in the insulating layers cannot move so it prevents the formation of convection currents.

Question 10

How do humans reduce heat loss from themselves?

Answer 10

• In the cold your hairs stand up on end to trap an insulating layer of air around the body
• Air pockets between you and your close reduced conduction and convection
• Clothes also reduces heat loss by radiation