Heat Transfer- The movement of heat from a warmer object to a cooler object.
1. Conduction Heat transfer by direct contact of molecules. In other words, when one molecule runs into another and it runs into another, etc. It can occur in a solid, liquid or a gas. Occurs best in a solid because the molecules are close together.
conduction
2. Convection Heat transfer by means of up and down movements called convection currents. Can occur only in a liquid or a gas
Convection currents Heated molecules do 2 things: 1. they expand, become less and then.. 2. they rise. Cooled molecules do the exact opposite: 1. they contract, become more dense and then… 2. they sink That is what makes a hot air balloon rise.
3. Radiation Heat transfer through open space. Occurs in a gas only.