Paper 1 - P1-P7

• Kinetic energy is the energy stored in moving objects.
• Stationary objects have no kinetic energy.
• When we stretch a spring, we're applying a force to change the length of the spring. Applying a force like this is called doing work.
• We're putting energy in to stretch the spring. The stretched spring is storing this energy and we call that energy elastic potential energy.
• Gravatational potential energy is the energy stored in an object due to it's position above the Earth's surface. This is due to the force of gravity acting on an object.
• The specific heat capacity of a substances is the amount of energy required to raise the temperature of 1kg of the substance by 1C.
• The law of the conservation of energy:

  Energy can be transferred usefully, stored or dissipated but it cannot be created or destroyed.
• A system is an object or a group of objects.
• In a closed system, no energy can enter or leave.
• Friction causes energy to be transferred to thermal energy.
• These stores of thermal energy are less useful. The energy has been dissipated (wasted).
• We can reduce unwanted energy transfers by reducing friction through:

  • using a lubricant e.g. oil on a fixed point
  • removing air particles
• Work is done whenever energy is transferred from one store to another.
• Mechanical work involves using a force to move an object.
• Electrical work involves a current transferring energy.
• Work done = Force x Distance
• Power is the rate at which energy is transferred or the rate at which work is done.
• Power = Energy transferred/time
• Power=Work done/time
• Efficiency= Useful output energy transfer/Useful input energy transfer
• Efficiency = Useful power output/Total power output
• The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction across that material.
• Modern houses are built from two layers: external brick and internal breezeblock. Between the walls there is a cavity.
• Builders pack the cavity with an insulating material which has a very low thermal conductivity.
• Double glazed windows and loft insulation = low thermal conductivity
• Reducing thermal energy transfer from a house:

  • Construct the building using materials with a low thermal conductivity
  • Build the house with thick walls as this also reduces the rate of thermal energy transfer
• Fossil fuesl: Coal, oil and gas
• Advantages of fossil fuels:

  • Reliable - always provide energy when we need it
  • They release a great deal of energy
  • Abundant and relatively cheap
  • Extremely versatile
• Disadvantages of fossil fuels:

  • Burning them releases a huge amount of carbon dioxide
  • Non-renewable - they're not being replenished as we use them
  • Release other pollutants - diesel: carbon particles and nitrogen oxides, coal: sulfur dioxide which leads to acid rain
• Nuclear power is non-renewable. Nuclear power plants run on the elements uranium and plutonium.
• Advantages of Nuclear Power:

  • Once a nuclear power plant is running it releases no carbon dioxide
  • Is extremely reliable. It generayes a lot of electricity exactly when we want it
• Disadvantages of Nuclear Power:

  • Contain in highly dangerous radioactive materials. If there's an accident then these materials could be released into the environment
  • Decommissioning a nuclear power plant takes many years and is extremely expensive
  • A nuclear power plant generates large amounts of highly radioactive waste. This must be stored for thousands of years before it's safe
• The UK has abundant reserves of coal. Up until the 1950s almost all of the electricity generated in the UK came from burning coal. Coal and coal gas were also used for almost all heating and cooking in the UK.
• In the 1950s, nuclear power came online and by the 1980s this produced around 20% of all the UK's electricity.
• In the 1970s, the UK became a major producer of oil and gas from the north sea and this began to replace coal.
• By 2000, as much electricity was generated from burning gas as from coal.
• Burning gas generates less carbon dioxide than burning coal. This contributes less to climate change.
• Gas-fired power stations are flexible. They can be switched unquickly during periods of high demand. Coal-fired power stations have a very long start-up time.
• In the 1970s, scientists began to realise that carbon dioxide emissions from human activity could be leading to climate change.
• The UK has one of the best locations for windpower. Over the last decade, the UK has opened a large number of wind-farms.