Energy conversion: the law of conservation of energy states that energy cannot be gained or lost, it can only be converted into another form. This is also known as the FIRST LAW OF THERMODYNAMICS. Here are some examples of energy transfers and conversions:

Heat energy can be transferred from one object to another by direct contact. This is called conduction.

Mechanical Kinetic Energy can be changed into heat energy

Chemical Potential Energy is stored in the magnesium Chemical Potential Energy is stored in the magnesium. It can be changed to heat energy by burning the magnesium

A list of alternative energy sources 1 A list of alternative energy sources 1. Methane from animal waste fermentation 2. Ethanol from fermented vegetation 3. Hydrogen from water by electrolysis or steam reformation 4. Tidal water potential 5. Geothermal 6. Waste vegetable oil from restaurants 7. Bio diesel 8. Solar (direct to make hot water; indirect to make electricity 9. Wind farming

Most energy is generated by combustion, that is, the burning of a fuel such as gasoline, natural gas, or heating oil, all of which are fossil fuels. The conditions for making this fuel no longer exist on earth, hence it is non-renewable.

In addition, this combustion is causing enormous problems of pollution and global warming due to the carbon dioxide which is produced as a by-product. Much research is directed toward implementing alternatives to this source of energy

Solar power Solar panels mounted on or near a house can generate electricity or heat water for the needs of the house’s occupants. This one is used to capture solar radiation and use it to heat water (note the water hoses). The panels are on a turntable, why? The panels are black, why?

A window wall in a passive solar house “harvests” the sun’s energy by changing it to heat. Roof panels can be used to heat water or to generate electricity.

Solar panels mounted on a car can provide the electricity to run an electric motor connected to the car’s wheel. Advantages? Disadvantages? car by Honda

Wind Power: The wind is a form of kinetic energy which can be used to turn a windmill to pump water, move a grind stone or generate electricity. Is the wind unaffected by the windmill? Is there any affect on the surrounding land?

Windmills have been in use in Holland for centuries to pump water invading from the sea (left). Modern wind machines pump water and generate electricity (right).

Wind farms harvest energy for conversion to electricity in California

Because there are no obstructions, there is more wind on the sea and greater potential for harvesting significant amounts of wind energy

Water power The heart of a hydro-electric plant is the generator. Magnets at 3 and 4 cause current to flow when the turbine blades at 7 are pushed by water flowing in from the water source ( a river or dam)

The turbines are typically huge and can generate megawatts of electricity. The moving parts are mostly under the floor where the water is pushing the blades

Geothermal: using the heat of the earth Hot spots around the globe can be utilized (right), but most modern geothermal simply uses the relatively constant temperature (around 100C) that exist hundreds of meters below the surface.

Geothermal energy can be used anywhere, since the earth below the surface is a relatively constant temperature.

Nuclear power plants in the USA

A typical nuclear reactor

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Ethanol: can be used in present internal combustion engines Ethanol: can be used in present internal combustion engines. Produced by fermenting sugar cane or corn stalks, etc. No new CO2 enters the environment; no sulfur, some nitric oxides

VEGGIE POWER: A small but growing group of modern do-it-yourselfers are converting diesel powered vehicles such as buses, trucks and the Volvo in the next slide to run on waste oil that is thrown away by restaurants.

Many chemical reactions illustrate the conversion of potential energy stored in the chemical bonds to other forms such as light, heat and sound.

Hydrogen gas powered sports cars:

This German bus is powered by the combustion of hydrogen gas; the only by-product is water.

FUEL CELLS: entrée into the Hydrogen Economy FUEL CELLS: entrée into the Hydrogen Economy. Using hydrogen and oxygen, in a kind of “cold combustion”, they produce electricity to run lap tops, cars, homes, ships, and even industry. They can be run backwards to split water into hydrogen fuel; to do this they need electricity which could be generated by solar cells.