ENERGY

Limited Energy Sources  Fossil Fuels –Coal: one of the first fossil fuel to be used widely during industrial revolution –Strip mining is used in which wide and deep holes are dug. These hole must be refilled in order to reduce effects of erosion etc. –Problem with coal is its transportation and it gives of sulfur dioxide during burning. –A new way to transport coal is to transport it through pipe lines in the form of slurry –Oil or ‘black gold’ is another fossil fuel. From it more fuels like gasoline and jet fuel can be prepared –Natural gas: it is used mainly for heating and cooking

Limited Energy Sources  Fossil Fuels –Magnetometer, seismograph and gravimeters are used in high-tech search for oil

Limited Energy Sources  Nuclear Fuels –Uranium is a nuclear or atomic fuel –E = mc 2 (speed of light c= miles/sec) –Uranium 235 is bombarded with neutrons --- chain reaction –Nuclear energy is controlled by controlling the amount of neutrons --- nuclear power plant –Care should be taken to prevent radioactive gases from escaping into the air from a nuclear power plant –Nuclear wastes are stored in buried blocks of concrete or naturally occurring salt formations

Unlimited Energy Sources  Solar Energy –The sun provides enough energy for one whole year in just 15 min –Other forms of energy like wind energy (large air movements) are also caused by the sun –Active solar systems --- the sun’s heat is used directly for a heating job, e.g. solar collectors, parabolic reflectors, turning a turbine –Passive solar systems --- indirect use of sun’s heat, e.g. windows, walls and doors in houses –Solar or photo cells turn light into electricity –They can be used to charge batteries that run radio relay stations

Solar heater or Used for heating Solar cells or Used to generate electricity

Unlimited Energy Sources  Wind Energy –The sun’s unequal heating of earth –Wind powered boats and pumps have been used until the steam engine was invented –Today the wind is used to generate electricity –Disadvantages : cannot operate when the wind blow is not at a certain speed, large wind-powered generators are noisy  Gravitational Energy –The energy of falling water is used to run today’s version of water wheel, the turbine --- hydroelectricity –Tidal energy is being used experimentally to make electricity

Unlimited Energy Sources  Geothermal Energy –The earth’s center is a hot molten core –At 3 miles below the surface of the earth, the temperature is around 600 o F –Earth geysers  Fusion –Another way of changing matter into energy –Huge amount of energy is released when the nuclei of two atoms are forced together –The fusion of two atoms requires a temperature of over 100 million degrees F –Fusion power plants will use deuterium and tritium as fuel

Renewable Energy Sources  Humans and Animals –An important source of energy  Biomass –It is vegetation or animal wastes –Direct combustion --- burning of waste products –Gasification --- methane gas (a fuel) is produced as biomass rots –Fermentation --- uses microorganisms to turn biomass such as grain into alcohol and carbon dioxide –Gasohol is a mixture of gasoline and alcohol  Wood –4 ft  4 ft  8 ft piece of wood can provide the same amount of energy as about 200 gallons of oil –Forests must be carefully managed

Energy from Biomass