Studied by 2 people
From hotter areas to colder areas
Direction of transfer of thermal energy
Conduction
Convection
Radiation
Ways thermal energy can be transferred (3)
Main method of thermal energy transfer in solids
Conduction
Free delocalised electrons collide with atoms, helping to transfer vibrations through the material and hence transfer heat through the metal quickly
Metal are very good conductors
Strong intermolecular bonds between particles make transfer of KE more rapid
Solids are good conductors
Non-metals, liquids and gases
Insulators
Atoms bump into eachother transferring KE
Intermolecular forces allow vibrations to pass between them
Heating a substance (2)
The transfer of heat through fluids (liquids and gases)
Convection
A fluid is heated
Molecules are pushed apart and the fluid expands
Hot fluid becomes less dense than surroundings
It rises and cold fluid (surroundings) moves to take its place
Hot fluid eventually calls and sinks back down again
Convection current (5)
The transfer of heat energy by IR waves
Thermal radiation
Emits more IR in a given time
A hotter object
Good absorber and emitter
Black surface
Poor absorber and emitter
White surface
Ok absorber and emitter
Dull/rough surface
Very poor absorber and emitter
Shiny surface
Can only occur through radiation, not conduction or convection
Heat transfer in a vacuum
Note 
Flashcard (50)