Thermal Physics

Question 1

conduction

Answer 1

the process where vibrating particles pass on their extra KE to neighbouring particles

Question 2

factors affecting conduction

Answer 2

temp difference
cross sectional area
length/ distance travelled
time

Question 3

convection

Answer 3

when particles move from a hotter region to cooler region taking thermal energy with them- transferring as they move

Question 4

fluid flow caused by changes in density (convection currents)

Answer 4

hot water becomes less dense
hotter particles rise
the hotter particles move v quickly and collide with the slow moving particles transferring thermal energy
the water molecules cool and become more dense
denser molecules move downwards

Question 5

factors affecting rate of convection

Answer 5

temperature gradient
relative movement of fluid
shape of container- most efficient in round square containers, inefficient in tall thin containers

Question 6

radiation

Answer 6

the transfer of heat using EM waves, typically IR

occurs in all types of matter

Question 7

factors affecting rate of radiation

Answer 7

surface area
volume
colour

Question 8

kinetic model of matter

Answer 8

solids have particles close together which vibrate in fixed positions

liquids have particles which slide past each other meaning the particles are more separated than solids and they also have weaker attractive forces

gases have particles that are free to move and have very weak attractive forces, particles move randomly and rapidly, they have v low density and can be easily compressed

Question 9

density formula

Answer 9

mass/volume

mass of 1 molecule x number of molecules per cubic metre

this can then be used to experimentally determine density