topic 3

• What are some energy stores?

  Chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear
• What is the formula for Kinetic Energy?

  KE=1/2mv^2
• What is the formula for GPE?

  GPE=mgh
• What is the law of conservation of energy?

  Energy cannot be created or destroyed, only transferred between stores
• How can energy be transferred?

  Mechanically, electrically, heating, radiation
• How can energy be lost during a transfer?

  Friction, air resistence, can be transferred to thermal stores. It is only useful when transferred to a useful store.
• What is the formula for efficiency?

  useful energy in/total energy out
• How can you reduce energy transferred by friction?

  - lubrication; using a liquid like oil so they can flow easily between objects and coat them
• How can you reduce the rate of energy transfer by heating?

  insulation:

  - double glazed windows

  - loft insulation

  - double glazed windows
• What are nonrenewable resources?

  Resources that cannot be replaced easily or reused.
• What are some examples of finite resources?

  coal, oil, natural gas
• What are some renewable resources?

  wind, hydro-electricity, geothermal, biomass, nuclear
• What are the advantages of wind turbines?

  - no pollution

  - minimal running costs
• What are the disadvantages of wind turbines?

  Power output is unreliable, can be noisy, cause visual pollution, not always windy, high initial costs
• What are the advantages and disadvantages of bio-fuels?

  - supposed to be carbon neutral (growing trees take sin CO2 released when they are burnt) but there is some debate bc it depends on the rate at which you grow the plants

  - cost to refine them is very high

  - some forests have been cleared to make room for biofuels, so animals lost teir habitats
• What are the advantages and disadvantages of hydro-electricity?

  - no pollution

  - big impact on environment due to flooding a valley, so habitats are permanently altered.

  - initial costs are high, but running costs are low, and it is a reliable resource
• What are the advantages and disadvantages of solar cells?

  - no pollution, but they do require a lot of energy to make

  - you can't produce it at night, or increase the enrgy you capture to keep up with demand
• What are the advantages and disadvantages of tidal barrages?

  - no pollution, but it can affect boat access, spoil the view and permanently alter the habitat

  - high initial costs, non fuel costs, minimal running costs

  - pretty reliable resources
• What are the advantages of non-renewable resources?

  cheap, easily to store, low running costs
• What are the disadvantages of non-renewable resources?

  - can release sulphur dioxide or carbon dioxide when burnt

  - contribute to acid rain and the enhanced greenhouse effect

  - add to air pollution in cities, worsening or causing respiratory illnesses, especially in bigger cities.