Notes

Heat energy can move through a substance by conduction. Metals are usually good conductors of heat, but non-metals and gases are usually poor conductors of heat. Poor conductors of heat are called insulators. Liquids and gases are fluids. The particles in these fluids can move from place to place. 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. All objects give out and take in thermal radiation, which is also called infrared radiation. The hotter an object is, the more infrared radiation it emits. Infrared radiation is a type of electromagnetic radiation that involves waves. No particles are involved, unlike in the processes of conduction and convection.