Energy revision

Types of energy: Chemical, heat, sound, light, kinetic, magnetic, elastic, Gravitational potential

Principal of conservation of energy:Energy can be changed from one form to another but the total amount of energy does not change

Energy is measured in: Joules

1 joule can: Lift an apple vertically by 1m

Renewable energy: Energy that is collected from resources that will never run out or which are naturally replenished within a human lifetime

Examples of renewable energy: Sun, wind, hydro, tidal, waves, wood/biofuel, geothermal

Non renewable energy: has a finite supply and will run out

Examples of non-renewable energy: Coal, oil, Gas

Nuclear power is non-renewable as supplies of uranium ore will eventually run out

Non-renewable energy sources can affect the environment, for example causing acid rain or global warming (greenhouse gases)

Efficiency:A measure of how much of the input energy to a process appears as useful output energy. Measured in a decimal or percentage

Efficiency = Useful output energy / total input energy

Work: When energy changes from one form to another

Work done = Force X Distance

Work done must be in Joules, Newtons and Metres

1 kilogram = 10 Newtons

Power is the amount of Work done/ energy transferred in one second, and is measured in watts or joules per second.

Power = energy transferred/ time taken

Kinetic energy = ½ X mass X velocity squared

Kinetic energy is calculated using Kilograms and Metres/second

Gravitational potential energy is because of an object’s position above the ground

GPE = mgh (mass X height X gravity)

GPE is calculated using vertical height in metres and mass using Kilograms

Windows can be insulated against conduction via double glazing.

Walls can have a space in the centre to stop conduction heat loss.

Walls can have foam inside them to stop heat loss through convection currents