Physics 1 - Heat (thermal energy)

?
  • Created by: Ls
  • Created on: 17-05-14 12:09
brownian motion (3)
smoke particles 'jiggle', they are being constantly hit by fast moving air particles, change direction each time they are hit
1 of 18
kinetic theory (2)
everything is made of particles which are always moving/vibrating, used to explain properties of matter: expansion, change of state and diffusion
2 of 18
heat transfer
heat always moves from hot to cold; conduction, convection, radiation
3 of 18
conduction (2)
heat travels from atom to atom; occurs in solids: particles vibrate when heated and pass the kinetic energy when they touch other particles
4 of 18
metals (conduction)
good conductors because of free-moving electrons, which travel through the metal, transferring the energy more quickly
5 of 18
gases and liquids (conduction) (3)
most liquids are poor conductors of heat; gases are very poor conductors; air is an insulator: has no free electrons
6 of 18
convection (2)
when fluids are heated, they expand, become less dense and rise carrying heat, cold fluids replace hot fluids and a convection current is created
7 of 18
thermals
rising hot air, keeps a glider up in the air because it creates a force on the glider
8 of 18
convection current
caused by molecules gaining more energy when hot
9 of 18
radiation (3)
transfer of energy by electromagnetic waves, heat can travel by infra red radiation and can travel through a vacuum
10 of 18
emitting radiation
something is hot and likely to cool down (better emitters cooll down faster) : silver>white>...>glass black>matt black
11 of 18
absorbing radiation (2)
something in a hot place and likely to heat up (better absorbers heat up faster) : silver>white>...>glass black>matt black; better reflectors heat up more slowly: silver>white>...>glass black>matt black
12 of 18
greenhouse effect
sun rays have short wavelength, gets through greenhouse gases and absorbed by Earth, it gets warmer and radiates Infra-Red rays with longer wavelength but can't get radiated out because Earth is not as hot as the sun
13 of 18
expansion (3)
as objects get hotter, they expand (pushing forces) and when they cool down, they contract (pulling forces); liquids expand more than solids but less than gases
14 of 18
evaporatio (in our body) (3)
a liquid in our body takes energy from it to change state by evaporation; faster (hot) molecules leave and slower (cold) ones stay behind until our body warms them; when we sweat, it takes latent heat from our body and evaporates
15 of 18
evaporation depends on...
temperature, dryness of the air, wind and surface area
16 of 18
latent heat
the energy needed from particles to change state without them actually changing temperature
17 of 18
rate of thermal energy
depends on: shape, dimensions, mass, material, what the object is in contact with and the temperature difference between an object and its surroundings (bigger the faster)
18 of 18

Other cards in this set

Card 2

Front

everything is made of particles which are always moving/vibrating, used to explain properties of matter: expansion, change of state and diffusion

Back

kinetic theory (2)

Card 3

Front

heat always moves from hot to cold; conduction, convection, radiation

Back

Preview of the back of card 3

Card 4

Front

heat travels from atom to atom; occurs in solids: particles vibrate when heated and pass the kinetic energy when they touch other particles

Back

Preview of the back of card 4

Card 5

Front

good conductors because of free-moving electrons, which travel through the metal, transferring the energy more quickly

Back

Preview of the back of card 5
View more cards

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Heat (thermal energy) resources »