2023-08-31T04:53:08+03:00[Europe/Moscow] en true Energy, Kinetic or potential, Energy transfers, Energy transformations, Heat (thermal energy, Chemical energy, Units of energy, Power, Energy sources, Producing electricity, Fossil fuels, Coal, Petroleum, Gas, Fracking, Nuclear energy, Heat collectors, Flat plate collector, Evacuated tube collector, Photovoltaic (PV) cells, Pure silicon, Wind energy, Turbines, Location of turbines, Hydroelectric power, Con and negs of dams, Tidal power, Wave power, Geothermal, Biomass energy, Biogas, Wood, Ethanol, Hydrogen flashcards
ev ch 14 unit 4 aos 2

ev ch 14 unit 4 aos 2

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  • Energy
    The capacity to perform work. When energy is transferred from an object, it can perform useful work
  • Kinetic or potential
    due to motion or position
  • Energy transfers
    occur when energy stays in its same form but moves from one object/location to another.
  • Energy transformations
    occur when energy is changed from one form to another.
  • Heat (thermal energy
    Temperature is a measure of the average kinetic energy within a material. Objects in contact, the hotter (exothermic) transfers (endothermic) to the cold object.
  • Chemical energy
    potential energy from position of atoms and electrons, converted via combustion.
  • Units of energy
    a joule, would raise 1cm3 of water by 0.25 C. KJ, MJ.
  • Power
    The amount of energy available or used over a given time (e.g. joules per second) . Power (W) = energy (joules)/time (seconds). 1 watt is 1 joule/second
  • Energy sources
    renewable which lasts indefinitely through natural processes, or non renewable which is exhaustible and limited deposits.
  • Producing electricity
    a source of energy is used to drive a generator of turbine from a flow of electrons.
  • Fossil fuels
    like coal, petroleum, gas from dead or decaying organisms.
  • Coal
    most used, usually in bottom layer of swamp, further compression leads to black coal, with less peat and high carbon.
  • Petroleum
    crude oil, heated in a refinery to make different products, usually fuel, its 25 per cent energy efficient. Hydrocarbon.
  • Gas
    burnt off with oil as waste, transport in pipes, mostly methane, used for heating and cooking.
  • Fracking
    aka coal seam gas, high pressure injections into the subterranean layer to have gas flow to the surface. May contaminate water.
  • Nuclear energy
    uranium in nuclear reactor by fission reaction, by neutron striking nucleus with high mass number. The sun does this but we get 1 per cent of it.
  • Heat collectors
    black plastic or rubber tubing, which water flows and is heat by.
  • Flat plate collector
    black metal absorber plate with tubes bonded, up to 100 C. Into an insulated tank, usually for back up.
  • Evacuated tube collector
    up to 200 C, held by a vaccum in a glass tube, usually industrial use.
  • Photovoltaic (PV) cells
    made from silicon, which is a semi-conductor (ie. Materials that will only conduct electricity under certain conditions). 15 per cent efficient. - doesn’t produce pollution, but sand mining has a huge effect
  • Pure silicon
    is lattice form, very stable, few free electrons isn't good for electricity.
  • Wind energy
    is a form of solar, from heated and cooled wind circulation. 45 efficient, even 70%, pitch may interfere with communication signals.
  • Turbines
    propeller than spins when wind is caught in the blades, into the shaft, vertical turbines more effective than horizontal.
  • Location of turbines
    strong wind area, most effective and away from turbulence, in clear, elevated space.
  • Hydroelectric power
    stored water in dams, depends on volume and vertical distance to fall.
  • Con and negs of dams
    Gravitational potential energy converted into kinetic, then generator into electrical, 70% efficient. Flooding can happen, diversion of water from rivers, thermal pollution from cold water.
  • Tidal power
    similar to hydroelectric but incoming and outgoing tides generate power. Very few though worldwide.
  • Wave power
    dependent on height and period of wave front, system of floats use movement of water to compress air or lift fluid thus generating electricity.
  • Geothermal
    high pressures and tempurature in thin crust, steam generate like portland which around 60 C, iceland 95% use it. Removal of water would reduce watertable.
  • Biomass energy
    is energy that originated from material produced by living things e.g. waste from forestry products or animal/human waste.
  • Biogas
    methane and co2 mixture, for house heating.
  • Wood
    30 per cent of world. 10% efficient, smoke = air pollution, deforestation
  • Ethanol
    biofuel from carbs fermented and distilled. Blend with petrol, reduce ghg emissions. But aldehydes make photochemical smog like new york.
  • Hydrogen
    combustion using exothermic reaction usually from water or hydrocarbons from electrolysis Little pollution but used in industrial process and is expensive.