Term | Definition |
Degrees Celsius | Unit for measuring temperature |
Evaporate | When a liquid turns into a gas |
Internal energy | Energy stored in the movement of particles. Also called thermal energy. |
Joule | Unit for measuring energy |
Temperature | How hot something is |
Thermal energy | See internal energy |
Absorb | To soak up or take in |
Conduction | Transferring energy touching |
Convection | Transferring energy by circling currents in fluids and gases |
Density | The amount of mass that one cubic centimetre of a substance has |
Emit | To give out |
Fluid | A gas or a liquid |
Infrared radiation | Transferring energy by waves through space |
Medium | Any substance through which something travels |
Radiation | Electromagnetic waves that travel through space. Includes light, gamma, radio, infrared, X-ray, microwave and ultraviolet waves. |
Reflect | To bounce off a surface |
Thermal conductor | Allows heat to be transferred through it |
Thermal imager | A device that takes pictures of infrared radiation instead of light radiation |
Thermal insulator | Does not allow heat to be transferred through it |
Solar cell | A material that directly converts light radiation to electrical energy |
Solar panel | A material that transfers the Sun’s infrared radiation to heat water |
Appliance | A household instrument powered by electricity |
Efficiency | A way to describe how much energy is wasted |
Kilowatt | A unit for measuring power kW 1000W = 1kW |
Watt | A unit for measuring power 1W = 1J per second |
Power rating | The number of joules of energy an appliance uses every second |
Sankey diagram | A diagram showing energy transfers where the width of each arrow is proportional to the amount of energy it represents |
Kilowatt-hour | The amount of energy used by a 1kW appliance in one hour. 1kW = 3600kJ. |
Payback time | The time it takes to get the money back that you spent on an energy-saving change |