What is coal?
Coal is a rock that burns (a solid hydrocarbon), formed from partially decayed plant matter that collected in a stagnant swamp and later was subjected to heat over time. Because all this happened millions of years ago it is called a "fossil fuel". Oil and natural gas are the other fossil fuels. There are different types of coal depending on the degree of coalification (amount of heat and time):
- Peat
- Lignite
- Subbituminous coal
- Bituminous coal
- Anthracite coal
- Rank the percent of carbon present (subbituminous, bituminous, anthracite)
- Grade the amount of ash that forms when burned (low ash, med ash, high ash)
Subbituminous coal...........8,000 to 10,000 BTU*
Bituminous coal................10,000 to 14,000 BTU
Anthracite coal..................12,000 to 14,000 BTU
*A BTU is a British Thermal Unit and is equal to the heat in one kitchen match.
Coal provided the power for the Industrial Revolution and today is used to generate over half of the electricity used in the U.S. It is also used in the chemical industry to make all manner of things including plastics, synthetic fabrics, medicines etc. It may also be converted to natural gas.
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