Petroleum, also called crude oil,
is a
naturally occurring liquid found beneath the earth's surface
that can be refined into fuel. A fossil fuel, petroleum
is created by the decomposition of organic matter over time and
used as fuel to power vehicles, heating units, and machines,
and can be converted into plastics.
Petroleum
is a
complex mixture of naturally occurring hydrocarbon
compounds found in rock which has been formed over
thousands of years by heat and pressure turning
organic matter to oil and gas. Impurities such
as sulphur, oxygen and nitrogen are common in
petroleum.
Petroleum has
historically been the largest major energy
source for total annual U.S. energy
consumption. We use petroleum
products to
propel vehicles, to heat buildings, and to
produce electricity.
