Energy

• What are the different kinds of energy stores?

  • kinetic energy
  • thermal energy
  • GPE
  • EPE
  • Chemical energy
  • magnetic energy
  • electrostatic energy
  • nuclear energy
• How is energy transferred?

  Energy is transferred mechanically, electrically, by heating or by radiation.
• Define the conservation of energy.

  Energy can be transferred, stored or dissipated but can never be created or destroyed.
• What is conduction?

  Conduction is the process where vibrating particles transfer energy to neighbouring particles.
• What is conduction?

  Conduction mainly takes place in solids and the particles in the object being heated vibrate more and collide with eachother which causes energy to be transferred to the kinetic energy store. The process continues throughout the object until it is transferred to the other side of the object and then transferred to the surroundings.
• What is convection?

  • energetic particles move away from hotter to cooler regions
  • happens in liquids and gases - shared across the kinetic energy store
  • particles able to move and when heated the particles move faster and the space between particles increases making the density decrease
  • because they can flow, the warmer and less dense region will rise above denser, cooler regions
• How to reduce unwanted energy transfers - lubrication?

  • when something moves, at least one frictional force is acting against it which causes energy in the system to be dissipated
  • lubricants can reduce the friction between objects that rub together so they can flow easily and coat them
• How to reduce unwanted energy transfers - insulation?

  • thick walls - made of material with a low thermal conductivity which slows the rate of energy transfer
  • cavity walls - made up of an inner and outer wall with an air gap which reduces the amount of energy transfers by convection through walls
  • cavity wall insulation - air gap filled with a foam to reduce transfers in wall cavity
  • loft insulation
  • double glazed windows - work the same as cavity walls
  • draught excluders
• What are non-renewable energy sources?

  • coal, oil and natural gas
  • although being reliable, they cause damage to the environment and with all 'run out' eventually
  • form underground for millions of years
  • typically burnt to provide energy
  • fossil fuels and nuclear fuel
• What are renewable energy sources?

  • the sun, wind, tides, geothermal, bio-fuel, hydro-electricity, waves
  • they will never run out, they do damage the environment but not as bad, don't provide much energy as they are less reliable as it depends on the weather
• What is wind power?

  • loads of wind turbines in exposed places like on moors and near coasts
  • each turbine has a generator in it - the rotating blades turn the generator and generate electricity
  • no pollution - a little bit when manufacturing
  • spoils the view, turbines stop turning if there is no wind or the wind is too strong, impossible to increase supply when there is an extra demand
  • initial costs are high but no fuel costs - minimal running costs
• What is Solar Power?

  • generate electricity directly from the sunlight - best source to charge batteries
  • often used in remote places and to power road signs and satellites
  • no pollution - use a lot of energy in the manufacturing
  • in sunny countries it is very reliable but only in daytime, can be cost efficient in cloudy countries
  • can't increase the energy output when there is a demand
  • initial costs are high but no running costs and energy is free
  • used to generate electricity on a small scale
• What is geothermal energy?

  • possible in volcanic areas or where hot rocks are near the surface
  • brilliant free energy that is reliable and does little damage to the environment
  • used to generate electricity and heat buildings directly
  • not many suitable locations for power plants
  • cost of building power plant is very high
• What is hydro-electric power?

  • requires flooding a valley by building a big dam - water allowed to flow through turbines when generates electricity
  • no pollution, provides an immediate response to an increase in demand for electricity, very reliable (droughts can change this), no fuel costs, low running costs
  • big impact on the environment due to the flooding and loss of habitat for some species, reservoirs look unsightly when dried up
• What is wave power?

  • lots of wave powered turbines around the coast - connected to a generator
  • no pollution, very useful on small islands, no fuel costs, minimal running costs
  • disturbs sea bed and habitats of marine animals, spoils the view, hazard to boats, fairly unreliable as waves die out when the wind drops, don't produce energy on a large scale, initial costs are high
• What is tidal power?

  • tides are used in a lot of ways - tidal barrages being one which are big dams built across river estuaries, with turbines in them. Water flows through the turbines in a controlled speed.
  • tides created by moon and the sun
  • no pollution, reliable, no fuel costs, low running costs, generates a significant amount of energy
  • prevents free access by boats, spoils view, alters habitats
• What are bio-fuels?

  • created from either plant products or animal dung - can be any state and are burnt like fossil fuels but are renewable
  • carbon neutral (debatable)
  • fairly reliable
  • large areas of forest have to be cleared, cannot respond to immediate energy demands, high costs, not enough space or water to meet demands for crops