paper 1

• Energy Stores

  • Elastic potential
  • Gravitational potential
  • Thermal
  • Electrostatic
  • Nuclear
  • Chemical
  • Kinetic
  • Magnetic
  • Light
  • Sound
• How is energy transferred?

  1. Mechanically - force doing work

  2. Electrically - work done by moving charges

  3. Heating/Radiation - light, sound
• Work


  When a current flows or by a force moving an object
• What happens when an object falls and there's no air resistance?
• SHC


  The amount of energy needed to raise the temperature of 1kg of a substance by 1°C
• What is the conservation of energy principle?
• Power


  The rate of energy transfer, or the rate of doing work
• Conduction


  The process where vibrating particles transfer energy to neighbouring particles
• Thermal conductivity


  A measure of how quickly energy is transferred through a material via conduction
• Convection


  Where energetic particles move away from hotter to cooler regions
• Convection currents

  Energy is transferred from the radiator to the nearby air particles by conduction

  1. The air by the radiator becomes warmer and less dense as the particles move quicker
  2. The warm air rises and displaces the cooler air, which is then heated by the radiator
  3. The previously heated air transfers energy to the surroundings - the air cools, becomes denser and sinks
• Thermal insulation techniques


  • Cavity walls

  Cavity wall insulators

  Loft insulation

  Double-glazed windows

  Draught excluders
• Non-renewable energy resources


  • Fossil fuels (coal, oil, natural gas)

  Uranium or Plutonium (nuclear power)
• Renewable energy resources


  • Wind power

  Solar power

  Geothermal power

  Hydroelectric power

  Wave power

  Tidal power

  Bio-fuels
• Burning fossil fuels is damaging to the environment
• Non-renewables will run out one day
• Pressure from other countries & the public has led to targets being set e.g the UK aims to use renewable resources to provide 15% of the total yearly energy by 2020
• Pressure being put on energy providers to build new power plants that use renewable resources to ensure that they don't lose business & money
• Reliability of renewable energy resources

  • Some energy resources aren't that reliable, a combination of different power plants would have to be used - expensive
• Cost of switching to renewable power


  • The cost will have to be paid & some people don't want to or can't afford to pay
• Politics of renewable energy

  • Companies and governments can't force people to change their behaviour
• When a system changes, energy is transferred - it can be transferred into/away from the system, between different objects in the system or between different types of energy stores
• Wind turbines


  • Large numbers of turbines would need to be built - takes up space & is expensive
  • Not always windy - the same amount of electrical power won't be produced every day
• Electric current


  The flow of electrical charge
• Electric current


  Measured in Amps
• Potential difference


  Voltage - it pushes the electric charge around the circuit
• Potential difference


  Measured in Volts
• Resistance


  Anything that slows the flow down
• Resistance


  Measured in Ohms
• The greater the resistance


  The smaller the current that flows
• The ammeter is placed in series
• The voltmeter is placed in parallel
• Ohmic Conductors have a constant resistance at a constant temperature, the current is directly proportional to the potential difference
• Resistance changes in Diodes and filament lamps
• In a filament lamp, as the electrical charge flows through it

  It transfers some energy to the thermal energy stores of the filament which is designed to heat up, therefore the resistance, temperature and current all increase
• Resistance is directly proportional to temperature
• LDR (Light Dependent Resistor)


  A resistant dependent on the intensity of light, in bright light the resistance decreases, in darkness the resistance is highest
• Thermistor


  A temperature dependent resistor, in hot conditions the resistance decreases, in cold conditions the resistance increases
• In a series circuit, the potential difference is shared between all the components, the current is the same in all components, and the total resistance is the sum of all the resistances
• In a parallel circuit, the potential difference is the same in all components, the current is shared between the components, and the total resistance is less than the resistance of the smallest of the two resistors