Energy

• 8 Energy Stores are Thermal, Kinetic, Gravitational Potential, Elastic Potential, Chemical, Magnetic, Electrostatic and Nuclear
• Closed Systems= Energy cannot be transferred from the system to the surroundings.
• 4 Energy Pathways are Mechanical, Electrical, Heating and Radiation
• Work Done is Energy Transferred
• Kinetic Energy= 0.5 x mass x speed squared
• Gravitational Potential Energy= Mass x Gravitational Field Strength x Height
• Elastic Potential Energy= 1/2 x spring constant x extension squared
• Specific Heat Capacity= energy required to raise the temperature of 1kg of a substance by 1 degree
• Energy cannot be created or destroyed only transferred, stored or dissipated
• Dissipated Energy is sometimes called wasted energy
• Power= energy transferred/time taken to transfer energy (Watts)
• Power is the rate of doing work
• Conduction= the transfer of heat energy from one object to another through the movement of particles
• Convection= the transfer of heat by the movement of hot and cold air, water or other liquids
• Lubrication of parts reduces wasted energy
• Insulation reduces wasted heat loss
• Some houses cavity walls to prevent heat loss
• Efficiency= useful energy output/ total energy input
• Less energy wasted, more efficient a device is
• No device is 100% efficient
• Non Renewable Energy sources include Oil, Natural Gas and Coal
• Renewable Energy Resources include Solar, Wind, Bio-Fuel, Tidal and Geothermal
• Advantages of non renewable resources are that they can be used quickly and easily, have high power density (energy per unit volume) and are cheap.
• Disadvantages of non renewable resources are that they cause pollution, run out eventually and produce greenhouse gases which contribute to global warming.
• Advantages of renewable resources are that they don't pollute the environment or produce greenhouse gases, they are sustainable as long as we look after them properly and some are free such as wind and solar.
• Disadvantages of renewable resources are that they take up lots of space, aren't always reliable due to weather conditions and require large amounts of land
• Energy Resources can be used for Transport, Petrol in cars and Hydrogen in Hydrocars
• Wind Power is are non-polluting but can be expensive to install and maintain and are not as efficient at producing energy
• Solar Cells are expensive and reliant on the sun, so they are not suitable for all areas
• Geothermal Energy can only be used in volcanic areas
• Hydro-Electric power uses the force of falling water to turn a turbine to generate electricity
• Hydro-Electric is damaging to the environment but is reliable
• Wave Power is fairly unreliable but no pollution
• Tidal Barrages use the tides to generate electricity.
• Bio-Fuels are made from plants and waste products and are used as a substitute for fossil fuels
• Bio-Fuels are fairly reliable and can be used in cars and planes. They are also renewable and can be grown in a sustainable way.
• Currently, we depend on fossil fuels but this is damaging to the environment
• The main problem with renewables is that they aren't always available so we need to store energy when it is produced
• Solar panels convert light into electrical current using photovoltaic cells