Yr10 mock

• Energy change stores


  • Chemical potential energy (food + fuel)
  • Gravitational potential energy
  • Elastic potential energy (stretched objects)
• Elastic potential energy


  Energy stored in compressed or stretched objects
• Elastic potential energy


  • Units: joules
  • Measured in newtons per metre
• Specific heat capacity


  The amount of energy needed to heat 1kg of a substance by 1°C
• Power


  The rate that energy is transferred or the rate at which work is done
• Power


  • Units: watts
  • Measured in joules per second
• Kinetic energy


  Energy possessed by a moving object
• Kinetic energy


  • Units: joules
  • Depends on mass and speed
• Gravitational potential energy


  Energy possessed by an object due to its position in a gravitational field
• Gravitational potential energy


  • Units: joules
  • Depends on mass, gravitational field strength, and height
• Change in thermal energy

  • Units: joules
  • Depends on mass, specific heat capacity, and temperature change
• Power is the rate of energy transfer or work done
• 1 joule per second is equal to 1 watt
• Energy cannot be created or destroyed, it can only be transformed (transferred, stored or dissipated)
• Thermal conductivity


  The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction through the material
• More efficient energy transfer has less wasted energy (higher efficiency)
• Efficiency


  A number between 0-100% that represents how much of the input energy is converted to useful output energy
• Making energy transfer more efficient

  1. Reducing friction

  2. Lubrication

  3. Thermal insulation
• Energy is always wasted, but it can be reduced through different ways
• Buildings with thinner walls or higher thermal conductivity

  Cool down quicker
• Efficiency


  Useful output energy / Total input energy
• National and global energy resources

  • Fossil fuels (coal, oil, gas)
  • Nuclear fuel
  • Biofuels
  • Wind
  • Hydroelectricity
  • Tides
  • Sun
  • Water waves
  • Geothermal
• Geothermal power generation


  1. Energy released by radioactive substances from deep in the earth heats up nearby rocks/soil

  2. This heat is used to produce steam which turns turbines
• Renewable energy sources


  • Geothermal
• Fossil fuels


  • Non-renewable
  • Produce carbon dioxide and sulphur dioxide (acid rain, global warming)
• Biofuels


  Made from plant material
• Advantages of biofuels


  • Renewable
  • Carbon neutral
  • No acid rain
• Disadvantages of biofuels


  • Less space for crops/food shortage
  • Destruction of habitats
  • Slower crop growth
• Energy resources


  Used in transport, electricity generating and heating
• Nuclear fuel


  Uranium and plutonium
• Advantages of nuclear fuel

  • No pollutant
  • More energy per kg
  • Reliable
• Disadvantages of nuclear fuel

  • Non renewable
  • Produces radioactive waste
  • Accidents could occur and spread radioactive material
• Solar panels


  Convert sun energy
• Advantages of solar panels

  • Renewable energy is free
  • No running costs
  • Useful for when little energy
• Disadvantages of solar panels

  • Expensive
  • Need lots of them
  • Need lots of sunshine (not nighttime) to make enough power
• Water and wind


  Turns turbines
• Advantages of water and wind

  • Renewable
• Disadvantages of water and wind

  • Not a constant supply
  • Sometimes noisy
  • May destroy habitats
• Open switch


  • Variable resistor
  • Lamp
• Closed switch


  • Fuse