P2 - Living for the Future

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Using the Sun's Energy

  • Sun gives out energy in the form of heat and light, some of this energy is stored as fossil fuels.

Photocells (solar cells)

  • Generate electricity directly from sunlight
  • Generate direct currect (DC)
  • Direct Current - current flows the same way around the circuit all the time

Usually made of silicon (semiconductor). When sunlight falls on the cell:

  • Silicon atoms absorb some of the energy, releasing some electrons
  • These electrons then flow round in a circuit, which is electricity

The current and power output of a photocell depends on:

  • Surface area (bigger the cells, more electricity produced)
  • Intensity of light (brighter, more electricity)
  • Distance from light source (closer the cell, more intense the light hitting it will be)


  • No moving parts - sturdy, low maintenance, last a long time
  • Don't need power cables/fuel
  • Renewable, doesn't pollute


  • No sunlight, no power
  • Not useful at night or when weather is bad

Solar and Wind Power

Passive Solar Heating

  • Passive Solar Heating - when energy from the Sun is used to heat something directly
  • Light from the Sun has a short wavelength - pass through glass into a room, but the heated things in a room emit infrared radiation from a longer wavelength (can't escape through glass) reflects back, just like the greenhouse effect

Wind Turbines

  • Energy from the Sun heats the atmosphere which causes convection currents, which produce wind
  • Wind turbines convert the kinetic energy of moving air into electricity
  • Wind turns the blades, which turn a generator


  • Cheap to run, tough and reliable, wind is free
  • No pollution
  • Wind power - renewable


  • Wind farms - visual pollution (spoil views)
  • Spinning blades - noise pollution
  • Wind isn't fast enough to generate power

Producting and Distributing Electricity

National Grid

  • It is the network of pylons and cables
  • It takes electricity from power stations to where its needed - homes and industry
  • It enables power to be generated and supplied anywhere on the Grid

Power Stations

  • STAGE 1 - use the fuel to produce heat which then generates steam (job of the boiler)
  • STAGE 2 - moving steam drives the blades of a turbine
  • STAGE 3 - rotating movement from the turbine is converted to electricity by the generator (using electromagnetic induction)


Type of Power Source :Fossil Fuels


  • Readily available
  • Concentrated solute of energy (little bits of coal gives out alot of heat)


  • Burning them - acid rain
  • Produces carbon dioxide

Type of Power Source: Biomass


  • Renewable
  • Carbon neutral


  • Need alot of biomass to replace on lump of coal
  • Takes alot of room to grow

The Dynamo Effect

  • Electromagnetic Induction (EM) - the creation of a voltage (and maybe current) in a wire which is experiencing a change in magnetic field
  • Dynamo Effect - when you use electromagnetic radiation to transform kinetic energy into electrical energy

Two different situations where you get EM induction:

  • Electrical conductor (coil wire is often used) moves through a magnetic field
  • Magnetic field through…


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