Thermal Energy and Heat

Thermal Energy and Matter Heat – transfer of thermal energy from one object to another because of temp. difference Heat flows spontaneously from hot objects to cold objects

Thermal energy – total PE and KE of all the particles in an object Temperature – measure of how hot or cold an object is compared to a ref. pt. Related to avg. KE of the particles in an object due to their random motion through space Thermal energy – total PE and KE of all the particles in an object

Thermal contraction – when the volume of a material decreases due to a decrease in temperature Thermal Expansion – increase in the volume of a material due to increase in temp.

Specific heat – amt. of heat needed to raise the temp Specific heat – amt. of heat needed to raise the temp. of 1g of a material by 1 degree Celsius

Heat and Thermodynamics Conduction – transfer of thermal energy with no overall transfer of matter Occurs within a material or between materials that are touching Occurs slower in gases than in liquids or solids Thermal Conductor – material that conducts thermal energy well Thermal insulators – poor conductor of thermal energy

Convection Convection – transfer of thermal energy when particles of a fluid move from one place to another

Convection currents – occur when a fluid circulates in a loop as it alternately heats up and cools down Important in many natural cycles such as ocean currents, weather systems, and movements of hot rock in Earth’s interior

Radiation – transfer of energy by waves moving through space All objects radiate energy Rate at which energy radiates increases with temp.