P4: Energy Resources and Energy Transfers

energy stores

• Chemical - fuel, food, batteries

• Electrostatic - energy stored when charged particles (electrons and protons) are in an electrical field and can attract or repel each other —> stationary e.g. balloon sticking to a wall

• Magnetic - magnets storing energy —> similar to electrostatic but magnets in a magnetic field —> caused by electrons spinning or moving in wires/materials —> moving e.g. magnets repelling each other

• Thermal - heat energy

• Elastic potential - stretched and compressed

• Nuclear - stored in atom nuclei

• Gravitational potential - stored when lifted

• Kinetic - moving objects

energy transfers

• Heating - conduction, convection, radiation

• Electrically - current flow

• Radiation - light and sound waves

• Mechanically - by a force moving

3 types of thermal energy transfer

1. conduction - heat through solids —> vibrating particles pass energy

2. convection - heat through fluids (liquids and gases) —> hot rise, cold sinks —> forms a current

3. radiation - heat by infrared waves —> no particles needed

what are dark, matte surfaces good at

absorbing and emitting radiation

what are shiny, white surfaces good at

reflect radiation well

how to reduce unwanted energy transfer

• insulation —> foam + double glazing (two layers of glass with a space of air between them)

• trapped air prevents convection

• shiny surfaces reduce radiation

what is the law of conservation of energy

GPE lost = KE gained when falling

energy isn’t made or gained or lost

what are the energy transfers for electricity generation

• fuel (chemical or nuclear)

• thermal

• kinetic (turbines)

• electrical

fossil fuels pros + cons

• pros = reliable, generates lots of energy

• cons = pollution, non-renewable

nuclear pros + cons

• pros = no CO2, generates lots of energy

• cons = expensive, radioactive waste

solar pros + cons

• pros = no pollution, renewable

• cons = weather-dependant, expensive

wind pros + cons

• pros = clean, renewable

• cons = noisy, unreliable

hydroelectric pros + cons

• pros = reliable, can start producing electricity quickly —> water is stored in dam —> water is released —> turbines start moving

• cons = requires building a dam which can flood large areas + disrupt river ecosystems

geothermal pros + cons

• pros = constant source —> underground

• cons = only in certain areas

tidal/wave pros + cons

• pros = predictable/reliable —> waves move and turbines move —> generates electricity

• cons = expensive + limited locations