Energy Flashcards
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