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Page 258
Visualizing the Formation of Fossil Fuels
Oil and natural gas form when organic matter on the ocean floor, gradually buried under additional layers of sediment, is chemically changed by heat and crushing pressure. The oil and gas may bubble to the surface or become trapped beneath a dense rock layer. Coal forms when peat - partially decomposed vegetation - is compressed by overlying sediments and transformed first into lignite (soft brown coal) and then into harder, bituminous (buh TYEW muh nus) coal. These two processes are shown below.
How oil and natural gas are formed
Ocean
Layer of sediment containing remains of dead marine organisms
Old ocean bed
Overlying layers of sediments
Layer of rock
Oil and natural gas formed by heat, pressure, and chemical reactions
Land
Ocean
Sediment
Layer of rock
Oil and gas
How coal is formed
Vegetation
Peat
New layers of overlying sediment
Increasing pressure and temperature
Lignite
New layers of overlying sediment
Increasing pressure and temperature
Bituminous coal
Page 280
Reacting to Nuclear Energy
Most people agree that thanks to energy sources, we have many things that make our quality of life better. Energy runs our cars, lights our homes, and powers our appliances. What many people don’t agree on is where that energy should come from. Almost all of the world’s electric energy is produced by thermal power plants. Most of these plants burn fossil fuels - such as coal, oil, and natural gas - to produce energy. Nuclear energy is produced by fission, which is the splitting of an atom’s nucleus. People in favor of nuclear energy argue that, unlike fossil fuels, nuclear energy is non polluting.
Opponents counter, though, that the poisonous radioactive waste created in nuclear reactors qualifies as pollution - and will be lingering in the ground and water for hundreds of thousands of years.
Supporters of nuclear energy also cite the spectacular efficiency of nuclear energy - one metric ton of nuclear fuel produces the same amount of energy as up to 3 million tons of coal. Opponents point out that uranium is in very short supply and, like fossil fuels, is likely to run out in the next 100 years. Opponents worry that as utilities come under less government regulation, safety standards will be ignored in the interest of profit. This could result in more accidents like the one that occured at Chernobyl in the Ukraine. There, an explosion in the reactor core released radiation over a wide area.
Supporters counter that it will never be in the best interests of those running nuclear plants to relax safety standards since those safety standards are the best safeguard of workers’ health. They cite the overall good safety record of nuclear power plants
This site at Yucca Mountain, Nevada, is the location of a proposed high-level nuclear waste storage facility. Here radioactive materials would be buried for tens of thousands of years.
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