What is heat conduction
When particles that are very close together transfer heat as they vibrate
Convection only occurs in
Fluids
What is convection
When the more energetic particles move from the hotter region to the cooler region and transferring energy as they do
Why are metals good conductors
They have a special structure that means their electrons are delocalised
Which block will ice melt quicker on: wood or metal?
Metal because conduction occurred- the metal transferred energy to the ice from the room
Describe convection
- as fluid heated the particles gain more energy and vibrate more
- so they take up more space
- so they are less dense
- less dense fluid rises above dense fluid
- cooler fluid falls to take place of hotter fluid
Process continues
Give one example of where convection is useful
Immersion heater (heater coils at the bottom corner of a domed tank)
Radiation doesn’t need particles to transfer heat
Radiation is a wave that can travel through a vacuum
What type of wave is radiation
EM Wave
Describe the experiment used to find the types of surfaces best at emitting heat radiation
Put boiling water in a Leslie cube
- wait a few minutes
- measure the heat coming off each side ensuring thermometer is the same distance each time
- repeat three times
Two different ways efficiency can be displayed in
Percentage
Decimal
Material that are bad conductors
Glass and plastic
Disadvantages of solar power
Don’t work in the night and in some climates
Visually unattractive
Takes up a lot of space
what is another way of saying energy transferred
work done
what is the unit for work done
joules or newton metres
advantages of fossil fuels
- reliable
- can produce large amounts of energy with fairly short notice
disadvantages of fossil fuels
- porduces significamt greenhouse gases and pollution
disadvantages of fossil fuels
- produces significant greenhouse gases and pollution
advantages of nuclear power
- reliable
- produces no greenhouse gases or pollution
- a large amount of energy is produced with a small amount of fuel
disadvantages of nuclear power
- produces dangerous amounts of radioactive waste that takes thousands of years to decay
advantages of bio-fuel energy
- the CO2 produced while burning the fuel is equal to the amount absorbed while making it
disadvantages of biofuels
- takes up a lot of land to grow and consumes resources needed for food production
advantages of wind energy
- produces no greenhouse gases
- the land around can still be used for farming
disadvantages of wind energy
- unreliable
- can be noisy and ugly
- not everywhere is suitable
