Transfer of thermal energy Flashcards
Temperature definition
measure of the average KE of particles in a substance
lowest possible temp
-273°C
Internal energy
define
Sum of KE and PE of all particles in a body
Kinetic Energy
define
energy due to motion of particles
Potential energy
Define
Energy due to forces between particles
Thermal energy
define
Energy tranferred between substances due to temperature differences
What is thermal conduction
Process of energy transfer where energy is transferred through thge opassing of vibrational motion fro one particle to another
What are good/poor thermal conductors
good: materials that transfer energy quickly by conduction
poor: AKA thermal insulators, materials that transfer energy slowly by conduction
Conduction in non-metals
Energy transferred to substance by heating –> particles nearest heat source vibrate more vigorously about fixed positions –> energy transferred from more energtic particle to neighbouring less energetic particles through collisions –> more energy transferred –> praticles vibrate mor evigorously –> increase in vibrational KE –> temp increase
Conduction in solids vs liquids&gases
particles of solids closer so KE transferred more quickly –> better thermal conductors
why are foam wool thermal insulators
contain pockets of still air –> thermal conduction cannot take place easily –> good insulator
define convection
process of energy transfer from one place to another by movement of heated gas or liquid due to differences in density
Define radiation
process of energy transfer by electromagnetic waves, does not require a medium
Factors affecting rate of radiation (4)
- Surface temperature
- surface area
- surface colour
- surface texture
