Energy Flashcards
What are the 8 types of energy store?
chemical kinetic gravitational elastic thermal magnetic electrostatic magnetic
What are the 4 methods of energy transfer?
Mechanically (whenever a force acts)
Electrically
By heating (conduction, convection, radiation)
by radiation of light and sound
Equation: Efficiency =
Efficiency = useful energy output / total energy input
What are the 3 methods of transfer of heat?
Conduction
Convection
Radiation
Describe conduction of heat.
Best in metals (as they have delocalised electrons)
Worse in air (particles long way apart)
Energy passed on by particles gaining energy and colliding with neighbouring particles to pass the energy along.
Describe convection.
Happens in liquids and gases Region of air heated, particles move quicker, take up more space. This less dense air rises Cooler air is more dense and sinks This forms a convection current
Describe radiation.
An electromagnetic waves that can travel in a vacuum
Shiny, white surfaces reflect radiation
Matt black surfaces absorb radiation so are the best emitters too
Describe the changes to radiation emitted is the surface becomes hotter.
More radiation emitted if the temp increases
Which 2 heat transfer types are prevented by cavity wall insulation?
conduction as air is trapped and air is a good insulator
convection as air is trapped and cannot form convection currents
How does a puffer jacket keep you warm?
trapped air stops heat transfer by conduction as air is a god insulator
trapped air also stops heat transfer by convection
Why wrap a marathon runner with a foil blanket at the end of the race?
shiny foil reflects the heat back to the runner preventing heat loss by radiation
Name the energy transfers when generating electricity by wind power.
kinetic energy store in the wind
transferred mechanically to
kinetic energy in the turbine
transferred electrically to peoples homes
Name the energy transfers when generating electricity by water power.
gravitational energy store in the water
transferred mechanically to
kinetic energy in the turbine
transferred electrically to peoples homes
Name the energy transfer when generating electricity using geothermal resources.
thermal energy store in the ground transferred by heating to thermal energy in steam transferred mechanically to kinetic energy store in the turbine transferred electrically to our homes
Name the energy transfer when using solar heating systems.
energy transferred by radiation from the sun
thermal energy store in the solar heating panels
