Energy (1)

• Define specific heat capacity 


  The amount of energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celsius
• Examples of chemical energy stores

  • Food
  • Fuel
  • Barteries
• Energy stores

  kinetic energy

  gravitational potential energy

  elastic potential energy

  chemical energy
• Law of conservation of energy


  energy cannot be created or destroyed only transferred
• Methods of reducing heat loss in a building

  Double glazing

  thicker walls

  loft and wall insulation
• Fossil fuels

  Reliable, enough to meet current demand, can increase energy produced when needed. Running out, release CO2 causing global warming, acid rain
• Biofuel

  Renewable, reliable, carbon neutral. High costs, requires space, clearance of natural forests
• Hydroelectricity

  Renewable, no pollution, can increase supply if needed. Big impact on environment. Animals and plants may lose their habitats
• Wave power

  Renewable, no pollution. Disturbs the seabed and habitats of animals, unreliable
• Tidal barrages

  Renewable, reliable, no pollution. Changes habitat of wildlife, fish can be killed in the turbines
• Main energy sources

  • Fossil fuels
  • Nuclear fuel
  • Biofuel
  • Wind
  • Hydroelectricity
  • Geothermal
  • Tidal barrages
  • Solar
  • Wave power
• Nuclear fuel

  Reliable, carbon free, high power output. High upfront cost, malfunctions can be catastrophic, produces nuclear waste
• Geothermal

  Renewable, reliable, rocks are always hot, power station have small impact on enviroment. Can release greenhouse gases, only found in specific places
• Wind

  Renewable, no pollution, no lasting damage to the environment, minimal running cost. Not as reliable, doesn’t work if there is no wind, cannot increase supply on demand
• Solar

  Renewable, no pollution, reliable in sunny countries. Lots of energy to build, don’t works during the day, cannot increase power if needed
• Unit for Mass

  Kilograms (Kg)
• Unit for speed

  v (m/s)
• Unit for elastic potential energy

  Ee (J)
• Unit for spring constant

  k (n/m)
• Unit for extension


  e (m)
• How to reduce energy waste

  • lubrication-> reduces friction
  • thermal insulation-> less useful thermal energy lost
• Explain the convection current:

  When a liquid or gas is heated, particles move faster

  -> so the liquid or gas becomes less dense

  The denser region rises above the cooler region