heat transfer Flashcards
conduction is heat transfer in …
solids
metals are better conductors because…
they have free electrons
why are glass,wood and rubber poor conductors
they don’t have free electrons - these are called insulators
explain conduction
1) particle is heated
2) particles and free elections vibrates and passes on the energy to the next particle
3) this happens until the whole solid has been heated
convection is the heat transfer in…
fluids (liquids or gas)
explain convection
1) the substance is heated, particles gain more kinetic energy
2) and move apart, the fluid expands
3) it becomes less dense and rises
infrared radiation is the heat transfer in…
a vacuum (no particles are involved) part of EM spectrum- travels at the sped of light
what objects emit and absorb infrared radiation
all objects emit IR (give off heat)
hotter objects emit more heat quickly than colder objects
dark matte surfaces ….
are good absorbers and emitters of IR
white, light surfaces….
are poor emitters of IR
shiny surfaces….
are good at reflectors of IR
what is specific heat capacity
SHC is the amount of energy required to raise the temperature of 1kg of a substance by 1 ºC
symbol for specific heat capacity measurement …
degrees ºC
SHC is measured in …
J/kg ºC
formulare for SHC is
E=Mc△T or E=Mcθ (θ=theta)
