Energy

• what happens when energy is transferred ?

  it is stored
• what are the eight stores ?

  • thermal
  • kinetic
  • gravitational potential
  • elastic potential
  • chemical
  • magnetic
  • electrostatic
  • nuclear
• how can energy be transferred ?

  by heating or by doing work
• what is a closed system ?

  a system where no energy can escape or enter
• describe kinetic energy

  • anything that is moving has kinetic energy stored
  • greater the mass the higher the speed and the higher the kinetic energy
• describe gravitational potential energy

  • lifting an object requires work causing energy to transfer to gravitational stores
  • depends on mass, height and strength
  • also transferred when an object falls
• describe elastic potential energy 


  stretching, squashing or bending an object transfers energy to elastic stores
• what is specific heat capacity ?

  the amount of energy needed to raise the temp of 1kg of a substance by 1°
• what is the conservation of energy ?

  • energy can be transferred, stored or dissipated
  • can never be created or destroyed
  • not all energy is transferred usefully
• what is power ?


  the rate of energy transfer or the rate of doing work
• what is the two ways of reducing unwanted energy ?

  • lubricants
  • insulations
• what does a lubricant do ?

  reduces frictional forces
• what does insulation do ?

  reduces lost heat energy
• how does a cavity wall work ?

  has an air gap which reduces energy transfer
• how does double glazed windows work ?

  the same as cavity walls
• what does loft insulation do ?

  reduces convection
• describe efficiency

  • less energy that is wasted, more efficient device is
  • no device is 100% efficient
  • wasted energy usually goes to thermal energy stores
• what is non renewable energy ?

  • will run out one day
  • damage the environment
  • provide most of our energy
• what are some examples of non renewable energy ?

  • coal
  • oil
  • (natural) gas
• what is renewable energy ?

  • they will never run out
  • damage environment less than others
  • don't provide much energy
  • unreliable
• what are some examples of renewable energy ?

  • sun
  • wind
  • tidal
  • biofuel
• describe wind power

  • wind turbines
  • no pollution
  • noisy
  • ugly
  • unreliable
• describe solar power

  • solar cells
  • no pollution
  • reliable (sometimes)
  • can't always meet demand
  • expensive
• describe geothermal energy

  • in volcanic areas
  • free and reliable
  • can heat or produce electricity
  • aren't many suitable locations
• describe bio-fuels

  • renewable
  • made from plant waste like fossil fuels
  • carbon neutral
• describe non renewable energy

  • fossil fuels and nuclear is reliable
  • can respond quickly to demand
  • contribute to greenhouse effect
  • acid rain
  • nuclear waste
• describe hydro electricity

  • requires flooding and building a dam
  • environmental impacts
  • immediate response
  • expensive but reliable
• describe wave power

  • no pollution
  • disturbs sea beds & habitats
  • unreliable
  • expensive
• describe tidal barrages

  • dams built across river estuaries
  • no pollution
  • reliable
  • habitats alter
  • expensive
• what are our trends in energy resources ?

  • mainly rely on fossil fuels
  • trying to increase renewable energy