Uses of Energy Transfer
Physics: Cambridge International GCSE Supplement, topic 2.3.8
Uses of Energy Transfer
Conduction, convection, and radiation are used a lot in everyday life.
Solar panels
- The solar panels that generate electricity are dark so that they can absorb the maximum amount of the sunlight hitting them.
Radiators
- Radiators are used for heating.
- A radiator’s primary way of heating a room is actually convection.
- If the primary way was radiation, then they should be painted black, as this is the colour that best emits radiation.
Vacuum flasks
- A vacuum flask keeps drinks hot or cold.
- Outside of the container, there is a vacuum layer (with no air in) surrounded by walls lined with silver.
- This reduces the heat transferred to the surroundings.
- The silvered walls are good reflectors and poor emitters of heat. This also reduces the heat transferred by radiation.
Heating in the kitchen pans
- Heat from the cooker is transferred to the pan by conduction (if on a hot plate) or by radiation/convection (if gas flame).
- The pan, usually made of metal, conducts heat quickly to the food.
- Energy is transferred from the hot surface of the pan to the cooler food, cooking it.
Fire burning wood or coal
- Energy stored chemically in the fuel is released as heat and light during combustion.
- Heat is transferred to the surroundings by infrared radiation, which can travel through air.
- Convection currents also carry warm air upwards, heating the room.
Radiator in a car
- The radiator transfers heat away from the engine to stop it from overheating.
- Hot coolant fluid from the engine passes through thin metal pipes in the radiator.
- Heat is transferred to the outside air by conduction (through the metal), convection (air moving past the radiator), and radiation (infrared emitted from the hot surface).
Test yourself on Uses of Energy Transfer
Why are solar panels black?
Which of the following statements are true of radiators?