conduction convection and radiation Flashcards
(12 cards)
how does conduction work
particles gain kinetic energy
they vibrate more
pass vibrations to neighbouring particles
why are metals good conductors
delocalised electrons move
+ collide with ions
transfers KE faster
because delocalised electrons move through material faster
what does convection happen in
fluids (liquids and gasses)
how does convection happen
particles gain KE/move faster
particles spread out
FLUID becomes less dense
warmer fluid rises
cooler fluid sinks
convection current
how type of wave is radiation and what does it travel through
infared = electromagnetic wave
travels though vacuum
what are matte black things good at?
absorbing and emitting infa-red radiation very well
what are properties of white shiny things
bad absorbed and emitter of infa-red radiation
what is a conductor
a material that allows heat (energy )or electrical energy to pass through it easily.
what is an insulator
something bad at transferring heat energy
6 marker on thermos bottle:
reduced heat transfer by conduction:
plastic lid is insulator, vacuum is no particles
reduced heat transfer by convection:
lid prevents flow of air
reduced heat transfer by radiation;
silver surface is poor absorber of IR
what does metal do as a good conductor
increase rate of heat transfer
what does trapped air do as a bad conductor
reduces heat transfer by conduction
