What is coal and how was it formed?
Coal is a nonrenewable hard black rock-like substance which is
burned to heat houses and produce electricity and was once used to
power trains and boats. It is made up of: carbon, hydrogen, oxygen,
nitrogen and varying amounts of sulphur.
When the geologists examine the fossil plants in coal, they find
the leaves and bark came from plants which no longer exist on
earth. They infer that these plants probably grew in moist warm
swampy forests roughly 300 million years ago. Over a period of time
the plants in these forests died, leaving layers of decaying wood
and other plant material. As more and more sediments were deposited
the weight of these layers forced out much of the water and gases
from the plant material, making it richer in carbon. Thus began the
slow change over millions of years from wood to coal.