ENERGY

1. ENERGY

2. 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

3. Limited Energy Sources • Fossil Fuels • Magnetometer, seismograph and gravimeters are used in high-tech search for oil

4. Limited Energy Sources • Nuclear Fuels • Uranium is a nuclear or atomic fuel • E = mc2 (speed of light c=186000 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

6. 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

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

8. 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

10. 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 600o 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

12. 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

13. Energy from Biomass