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Physics - Topic 1 - Energy (Conservation of Energy and Power (Power is the…

- - - - On average they only work 70-75% of the time.
      - Many complain of noise levels and how they distract from the view. This is because 1500 turbines are needed to cover the energy of just one coal power plant.
- - - - This process continues throughout the object until the energy is transferred to the other side of the object. It's then usually transferred to the thermal energy store of the surroundings.
    - - Materials with a high thermal conductivity transfer energy between their particles quickly.
  - - - This causes the density of the region being heated to decrease.
- - - - Thermal energy stores
      - Kinetic energy stores
      - Gravitational potential energy stores
      - Elastic potential energy stores
      - Chemical energy stores
      - Magnetic energy stores
      - Electrostatic energy stores
      - Nuclear energy stores
  - - - Energy is transferred electrically to the thermal energy of the kettle's heating element, which transfers energy by heating to the water's thermal energy store.
  - - - Work can be done when current flows (work is done against resistance in a circuit), or by a force moving an object.
    - - It causes an energy transfer from the chemical energy store of the person's arm to the kinetic energy store of the ball and arm.
    - - It causes energy to be transferred from the ball's gravitational potential energy store to its kinetic energy store.
    - - It causes an energy transfer from the wheels' kinetic energy stores to the thermal energy store of the surroundings.
    - - It causes energy to be transferred from the car's kinetic energy store to other energy stores. Some energy might be transferred away by sound waves.
- - - - The greater the mass and the faster it's going, the more energy there will be in its kinetic energy store.
  - - - This causes a transfer of energy to the gravitational potential energy store of the raised object.
        
        The higher the object is lifted, the more energy is transferred to this store.
- - - - Energy transferred / Time
      - Work done / Time
    - - A powerful machine is one which transfers a lot of energy in a short space of time.
- - - - This causes some energy in the system to be dissipated, e.g. air resistance can transfer energy from a falling object's kinetic energy store to its thermal energy store.
  - - - Thick walls - made from a material with a low thermal conductivity. The thicker the walls and the lower their conductivity, the slower the rate of energy transfer will be.
      - Use thermal insulation...
        
        Cavity walls - made up of an inner and outer wall with an air gap in a middle This reduces the amount of energy transferred by conduction through the walls.
        
        Cavity wall insulation - where the cavity wall air gap is filled with a foam - this can also reduce energy transfer by convection in the wall cavity.
        
        Loft insulation - reduce convection currents being created in lofts.
        
        Double-glazed windows - have an air gap between two sheets of glass to prevent energy transfer by conduction through the windows.
        
        Draught excluders around doors and windows reduce energy transfers by convection.
- - - - For example, if you use an electric drill, its energy transfers to lots of different energy stores, but quickly ends up all in thermal energy stores.
- - - - They can be solid, liquid or gas and can be burnt to produce electricity or run cars in the same way as fossil fuels.
  - - - This means that the power plants can respond quickly to changes in demand.
    - - For this reason, it is so popular.
  - - - Acid rain can be reduced by taking the sulfur out before the fuel is burned, or cleaning up the emissions.
- - - - This in turn pressures energy providers to build new power plants that use renewable resources so they don't lose business and money.
  - - - Some energy resources like wind power aren't as reliable as traditional fossil fuels. whilst others cannot increase their power output on demand.
        
        This would mean either having to use a combination of different power plants (which would be expensive) or researching ways to improve reliability.
      - Research on improving the reliability and cost of renewables takes time and money - it may be years before improvements are made even with funding. Until then, we need dependable, non-renewable power.
    - - Building new renewable power plants costs money, so some energy providers are reluctant to do so, especially when fossil fuels are so cost effective.
        
        The cost of switching to renewable power will have to be paid, either by customers in their bills, or through government and taxes.
        
        Some people don't want to or can't afford to pay, and there are arguments about whether its ethical to make them.
      - Making personal changes can be quite expensive. Hybrid cars are generally more expensive than equivalent petrol cars and thinks like solar panels for your home are pricey.
        
        The cost of these things is slowly going down, but they are still not an option for many people.
    - - If there are new power plants built, there are arguments over where to put them. Many people don't want to live next to a wind farm, causing protests.
        
        There are arguments over whether its ethical to make people put up with wind farms next to them when they may not agree with the reasons for their use.