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• System

  Either a single object or a group of objects
• Types of system

  • Open system
  • Closed system
• Open system


  Can exchange energy and matter with their surroundings
• Closed system


  Don't let energy or matter in or out
• In a closed system, the total energy remains the same, even though it might change form inside the system
• Energy


  Measured in Joules
• Energy follows the principle of conservation of energy, which tells us energy can not be created or destroyed, only transferred from one store to another
• Energy stores

  • Thermal energy
  • Chemical energy
  • Kinetic energy
  • Gravitational potential energy
  • Elastic potential energy
  • Nuclear energy
  • Magnetic energy
  • Electrostatic energy
• Energy transfer pathways

  • Mechanical work
  • Heating
  • Electric work
  • Radiation
• Kinetic energy


  Energy of moving objects, calculated using mass and speed
• Elastic potential energy


  Energy stored in elastic materials when stretched or compressed, calculated using spring constant and extension
• Gravitational potential energy

  Energy held by an object due to its height in a gravitational field, calculated using mass, gravitational field strength, and height
• Specific heat capacity

  Property that tells how much heat energy is needed to raise the temperature of 1 kg of a substance by 1 degree Celsius
• Water has a specific heat capacity of 4186 J/kg°C, meaning it takes 4186 Joules to heat 1 kg of water by 1°C
• Oil has a lower specific heat capacity of 1670 J/kg°C, so it needs less energy to heat up
• Thermal energy change

  Calculated using mass, specific heat capacity, and temperature change
• This experiment shows how to measure the specific heat capacity of a substance like aluminium
• Power


  The rate at which energy is being transferred or work is being done, measured in Watts
• The principle of conservation of energy states that energy cannot be created or destroyed, only transferred between different energy stores
• Energy dissipation


  Energy that is wasted or not usefully employed by a device
• Ways to reduce unwanted energy transfers

  • Cavity walls
  • Loft insulation
  • Double glazing windows
  • Draught excluders
• Friction converts kinetic energy into thermal energy, which is wasted
• Efficiency

  Ratio of useful energy output to total energy input, can be expressed as a percentage
• Reasons for energy dissipation in devices

  • Friction between moving parts
  • Air resistance
  • Electrical resistance
  • Sound
• Types of energy resources

  • Non-renewable resources
  • Renewable resources
• Non-renewable resources


  Finite resources that will eventually run out, usually cause environmental damage
• Renewable resources

  Replenishable resources, have minimal environmental impact but are generally less reliable
• Fossil fuels are non-renewable energy sources formed from ancient remains of living organisms
• Thermal energy is dissipated into the surroundings. If you can minimise these, you can improve the efficiency of a device.
• Types of energy resources

  • Non-renewable resources
  • Renewable resources
• Non-renewable resources

  Resources that we have a finite amount of, and will eventually run out of. They currently provide the majority of energy in the world. Their use usually results in environmental damage.
• Renewable resources

  Resources that are replenishable (will not run out). They do not produce much energy compared to non-renewable resources. They have minimal impact on the environment, however are generally less reliable than non-renewable resources.
• Non-renewable resources


  • Fossil fuels
  • Nuclear fuel
• Fossil fuels

  Energy sources formed from the ancient remains of living organisms. They include coal, oil, and natural gas. These fuels continue to be a major energy source worldwide due to their high energy content and ease of extraction.
• Nuclear power


  Uses energy from atoms, particularly uranium or plutonium, through a process called nuclear fission. This process releases a considerable amount of energy, and is then used to heat water, producing steam that drives turbines to generate electricity.
• Renewable resources

  • Wind power
  • Solar cells
  • Geothermal power
  • Hydro-electric power
  • Wave power
  • Tidal barrages
  • Bio-fuel
• Wind power

  Wind turbines use the kinetic energy from the wind to generate electricity. As the wind blows, it turns the blades of the turbine, which spins a generator inside the turbine's housing.
• Solar cells

  Solar cells, or photovoltaic cells in solar panels convert sunlight directly into electricity.
• Geothermal power

  Geothermal energy harnesses heat from the Earth's interior. Water or other fluids are pumped down to the hot regions, become heated, then return to the surface as steam or hot water. This steam rotates a turbine connected to a generator, producing electricity.
• Hydro-electric power


  Involves flooding a valley for the creation of large water reservoirs behind dams.