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Physics Kinetic Theory
Conduction
- A concept of I/GCSE physics, Conduction is the transfer of heat through solids,
- Conduction works best in metals
- Metals contain free electrons which gain energy when they gain heat, they are then able to pass kinetic energy along the metal.
- Metals are therefore good conductors • Other materials don’t contain free electrons.
- They are bad conductors but good insulators.
- Insulators keep heat in.
Convection
- Convection is heat transfer in liquids and gases (fluids)
- Convection can happen because as particles get warmer they become less dense and rise.
- The warmer particles are then at the top of the liquid/gas although the thing heating the liquid is at the bottom.
- The particles at the bottom rise as they are less dense and the colder particles fall.
- This is how the whole liquid/gas gets heated.
Radiation
- Radiation is the heat transfer that doesn’t require any particles
- All things give off Infrared radiation
- The warmer an object is the more radiation is given off
- Dark, matt surfaces are good emitters and absorbers of infrared radiation
- Light, shiny surfaces are good reflectors of radiation but poor emitters and absorbers.
Condensation and Evaporation
- Evaporation is when a liquid turns into a gas
- Particles have different energies in a liquid and therefore some escape and become
- The particles left over in the liquid have a lower average kinetic energy than before.
- The liquid cools down
- Condensation is when a gas turns into a liquid
- Particles in gases have different energies
- When a particle doesn’t have enough energy to be a gas it condenses and forms bonds with the other particles.
- This creates energy.
- To increase the rate of these two methods you:
- Increase the surface area
- Increase the draught over the substance
References:
- http://s2.thingpic.com/images/uF/Qdg2n6H1CrNryjuhxHNi5DtL.jpeg
- https://images.squarespace-cdn.com/content/v1/5cdecce138275f0001d2fd9b/1559604198390-5A58FI1E7ZTXIOIMYPIW/Water+Cycle+Graphic.jpg?format=1000w
That's the end of the topic!
Drafted by Kin (Physics)