P1

• Systems

  consists of either 1 object or a group pf objects

  Either open or closed -

  • open - exchange energy and matter with their surroundings
  • closed - energy or matter do not leave the system - total energy remains the same
• Energy

  Energy - measured in joules - cannot be created or destroyed - can only be transferred ( principle of conservation of energy )
• energy stores

  8

  • thermal - energy an object has because of its temperature
  • chemical - energy transferred by chemical reactions
  • kinetic - energy an object has because it is moving
  • gravitational potential- energy an object has due to its heigh above ground
  • Elastic potential - energy an elastic object has when it is stretched or compressed
  • nuclear - energy stored in the nucleus of an atom
  • magnetic - energy a magnetic object has when it is near a magnet or in a magnetic field
  • electrostatic - energy a charged object has near another charged object
• how energy is transferred

  4

  • forces (mechanical) - energy transferred when a force moves or changes the shape of an object
  • heating - energy transferred from an object with a higher temperature to an object with a lower temperature
  • radiation - energy transferred in the form of a wave
  • electricity - energy transferred by an electric current
• Energy transfers

  • ball thrown upwards by a person - chemical store in a person (from food) mechanically transferred to the kinetic energy store of the ball - ball slows down as it goes up - kinetic energy mechanically transferred to gravitational potential store
  • Kettle boiling water - energy transferred from the thermal energy store of the heating element by heating to the thermal store of the water
  • car accelerating with a constant force - energy transferred from chemical store of the car from the petrol mechanically to the kinetic energy store of the car
  • car braking - friction in the wheels causes energy to be transferred mechanically from the kinetic stor to the thermal store of surroundings
  • car crashing - energy transferred from kinetic energy store mechanically to the thermal store of the wall
• specific heat capacity

  The amount of energy required to raise the temperature of 1kg of a substance by 1°C
• Energy changes in systems

  Happens whenever you heat or cool an objects

  the amount of energy stored or released from a system can be calculated using the specific heat capacity
• Power

  The rate at which energy is transferred or the rate at which work is done
• What is work done?

  Energy transferred - measured in joules
• What is efficiency?

  How much energy is transferred usefully
• how are houses insulated?

  loft insulation

  double glazing

  draught excluders

  cavity wall insulation
• How does cavity wall insulation work

  Thicker walls - poorer conductors

  insulation - low thermal conductivity - reduced energy transferred
• What is thermal conductivity?


  How well a material conducts heat
• Ways to reduce energy transfer

  Lubrication - friction

  streamlining - air resistance
• energy transferred by heating in metals?

  Conduction
• Energy transferred by heating in gas and liquid

  convection
• What does insulation do?

  Reduce heat loss
• What is specific heat capacity?

  The snout of energy required to raise the temperature of 1kg of a substance by 1°C
• Can something be 100% efficient?

  No ❤️
• Non renewable resources?

  Will run out - used faster than they are replenished 🤰🏻

  are used for most of our energy 👻
• Renewable resources?

  Replenished at the same rate they are used - won't run out 🏊
• Coal? OIL? GAS?

  used for generating electricity

  OIL is used for transport and heating

  GAS is used for heating

  good-

  • Enough to meet current demands
  • reliable
  • cheap

  bad - ⚡️

  • will eventually run out 💨
  • release carbon dioxide - pollutes
  • OIL spills can KILL marine life 🐄
  • release OTHER pollution - sulfur dioxide (coal and OIL) acid rain
• what is reliable?

  Resources that are predictable and in sufficient quantities
• Nuclear energy 💣🌆🌆🌆

  Used for generating electricity

  good -

  • no greenhouse gases produced
  • enough available to meet current demands
  • large amount of energy transferred from a small amount of fuel
  • reliable

  bad-

  • produces NUCLEAR WASTE 🔥🔥🔥🔥🔥🔥 - difficult to dispose of - DANGEROUS - has to be stored before its disposed of
  • needs NUCLEAR POWERPLANTS - expensive to decommission- expensive to run and construct
• Solar energy 👎

  Renewable - used for electricity and heating

  bad -

  • dependent on weather
  • Expensive to buy and install 🐖
  • can't supply large scale demand

  good -

  • cheap to run
  • no pollution
• Hydroelectric

  Water flowing downhill turns generators- generates electricity

  good-

  • renewable
  • low running cost

  bad

  • dams expensive to build
  • need to flood a large area behind, destroying habitats and resulting in gas emissions from decaying vegetation
• Tidal

  Turbines on tidal barrages turned by water as the tide goes in and out

  good

  • predicable supply - tides always happen
  • can produce large amounts of electricity
  • no ghg and no fuel cost

  bad -

  • tidal barrages - restrict boat access - affect habitats and are expensive to build
  • Supply can't be controlled
• Wave

  Floating generators - generate power from waves moving up and down

  good -

  low running cost and no fuel cost

  bad -

  generators change habitats and can harm wildlife, retrict boat access and are expensive

  weather dependent
• Wind energy

  good

  • no fuel cost, low running cost

  bad

  • supply depends on weather
  • needs large amounts of land for wind farms
  • noise pollution
• Geothermal

  rocks in the curst generate heat

  good

  • reliable and renewable

  bad

  • only possible in some locations
  • power stations expensive to build
• Biofuels

  Fuel produced by living or recently living organisms

  good

  • carbon neutral
  • reliable and renewable

  bad -

  • expensive to produce
  • still produces greenhouse gases
  • growing requires a lot of land and resources
  • can lead to deforestation to make room
• Factors affecting energy transfer in houses

  Thickness of material (walls)

  temperature difference

  thermal conductivity