Energy

• System: Object or group of objects
• Closed system: Where no energy can go in or out
• 8 energy stores

  Kinetic

  Gravitational potential

  Elastic potential

  Thermal

  Chemical

  Nuclear

  Magnetic

  Electrostatic
• Kinetic energy: Energy an object has because its moving
• Gravitational potential: Energy an object has because of its height off the ground
• Elastic potential: Energy an elastic object has when it is stretched of compressed
• Thermal energy: Energy an object has because of its temperature
• Chemical energy: Energy that can be transferred by chemical reactions
• Nuclear energy: Energy stored in the nucleus of an atom
• Magnetic energy: Energy a magnetic object has when its near a magnet
• Electrostatic energy: Energy a charged object has when its near another charged object
• 4 ways energy can be transferred?

  Heating

  Waves

  Electricity

  Forces
• How is energy transferred by heating?

  Energy transferred from one object to another object with a lower temp
• How is energy transferred by waves?

  Waves can transfer energy by radiation
• How is energy transferred by electricity?

  When an electrical current flows it can transfere energy
• How is energy transferred by forces?

  Energy is transferred when a force moved or changed the shape of an object
• Thermal insulator: material with a low thermal conductivity (heat transfers occurs at a lower rate)
• Thermal conductivity: How well it conducts heat
• Work done: Energy transferred when a force moves an object
• The unit for energy: The joule (J)
• What equation links gravitational potential energy, mass, gravitational field strength, and height

  GPE = Mass x GFS x Height

  E(Small p) =mgh
• What equation links kinetic energy, mass, and speed

  Kinetic energy =0.5Mass x speed^2

  E(Small k) = 0.5mv^2
• What equation links power, energy transferred, and time

  Power = Energy transferred / time

  P=E/T
• Where does energy go

  Energy can only be transferred usefully, stored, or dissipated

  Useful: Energy transferred by light waves

  Dissipated: Transferred to the thermal store of the surroundings
• Lubrication: reducing unwanted energy transfer due to friction
• Streamlining: Way of reducing energy wasted due to air resistance of drag in water
• Efficiency

  Measure of how much energy is transferred usefully

  Efficiency = Useful power output / Total power output
• What are the main ways we use the Earths recourses?

  Generating electricity

  Heating

  Transport
• What is a renewable source?

  Can be replaced as quick as used

  Will not run out
• What is a non-renewable source?

  Cannot be replaced as quickly as used

  Will run out
• Carbon neutral: to remove the same amount of carbon dioxide from the atmosphere as was added by the burning of fossil fuels
• Coal Main uses, source, adv, disadv

  Main uses: Generating electricity

  Source: Extracted from underground

  Adv: Reliable, cheap

  Disadv: Pollution, non-renewable
• Oil Main uses, sources, adv, disadv

  Main uses: Generating electricity, transport, heating

  Source: Extracted from underground

  Adv: Reliable, cheap

  Disadv: Pollution, non-renewable
• Natural gas Main uses, source, adv, disadv

  Main uses: Generating electrity, heating

  Source: Extracted from underground

  Adv: Reliable, cheap

  Disadv: Pollution, non-renewable
• Nuclear fission Main uses, Source, adv, disadv

  Main uses: Generating electricity

  Source: Mining naturally occurring elements

  Adv: No pollution, reliable

  Disadv: Produces nuclear waste, expensive
• Solar energy Main uses, source, adv, disadv

  Main uses: Electricity, heating

  Source: Sun

  Adv: Cheap once installed

  Disadv: Depends on weather
• Hydroelectric energy Main uses, source, adv, disadv

  Main uses: Electricity

  Source: Water flowing downhill

  Adv: reliable, supply can be controlled

  Disadv: Expensive
• Tidal energy Main uses, source, adv, disadv

  Main uses: Electricity

  Source: Tide

  Adv: always tides

  Disadv: Harm wildlife
• Wave energy Main uses, source, adv, disadv

  Main uses: Electricty

  Source: Waves

  Adv: No pollution

  Disadv: Harm wildlife
• Wind energy Main uses, source, adv, disadv

  Main uses: Electricty

  Source: wind

  Adv: no pollution

  Disadv: depends on weather