Energy can be radiated/emitted and it can be absorbed
Dark, matt objects are good absorbers
Light, shiny objects are bad absorbers/good reflectors
States of Matter
Particles
Solid
fixed positions, vibrate, generally least energy
Liquids
move about at random, generally less energy than gas but more than solids
Gas
move about at random faster, further apart, generally most energy
Conduction
Metals are best
conductors
Materials like wool and fibreglass are best insulators
Non-metals are poor conductors because they don't contain free electrons
When a metal is heated the free electrons at the hot end gain kinetic energy
these electrons diffuse (spread out) and collide with other free electrons and ions in the cooler parts, transferring kinetic energy
metals contain a lot of free electrons, in non-metal solids the electrons are held in the atoms
Convection
Caused by heating a gas or liquid
Only happens in liquids and gases
Heating a gas or liquid makes it less dense so it rises and causes circulation
Condensation
Cooling by evaporation of a liquid is due to the faster-moving molecules escaping from the liquid
Evaporation can be increased by increasing the surface area of the liquid, by increasing the liquid's temperature, or by creating a draught of air across the liquid's surface
Condensation on a surface can be increased by increasing the area of the surface or reducing the temperature of the surface