Fossil Fuel Basics
Fossil fuels contain molecules called hydrocarbons, composed of hydrogen and carbon. When these molecules are heated, they react with oxygen in the atmosphere. This reaction produces new molecules and releases more heat. This heat can be used to generate electricity, heat homes, power cars and to accomplish many other purposes. Fossil fuels also contain sulfur, nitrogen and traces of heavy metals, which are released when they burn.
The hydrogen reacts with oxygen to produce H2O, or water. The carbon produces a lot of CO2 (carbon dioxide) and some CO (carbon monoxide) as well. Sulfur and nitrogen also combine with oxygen, producing sulfur oxides and nitrogen oxides. Some heavy metals and other pollutants are simply released into the air.
The worst effect of burning fossil fuels is global warming. When the sun shines on the earth, some of its energy is turned into heat and radiated back out into space. Carbon dioxide traps the heat, reflecting it back towards earth and warming it up. Some carbon dioxide in the atmosphere is necessary, since plants need it to survive. By burning fossil fuels, however, we release too much CO2, gradually increasing the planet's temperature. The sulfur and nitrogen oxides, meanwhile, get dissolved in water, increasing its acidity and creating acid rain. Aquatic plants and animals need a certain acidity to survive. When these chemicals make it into rivers, lakes and oceans, they can through off the balance and harm aquatic life. Some of the other byproducts of fossil fuels such as carbon monoxide and heavy metals are bad because they harm human health, causing respiratory disease and other conditions.