Petroleum is one of the most valuable natural resources in the world. Some people call petroleum black gold, but it may be better described as the lifeblood of industrialized countries. Fuels made from petroleum provide power for automobiles, airplanes, factories, farm equipment, trucks, trains, and ships. Petroleum fuels also generate heat and electricity for many houses and business places. Altogether, petroleum provides nearly half the energy used in the world.

In addition to fuels, thousands of other products are made from petroleum. These products range from paving materials to drip-dry fabrics and from engine grease to cosmetics. Petroleum is used to make such items in the home as aspirins, carpets, curtains, detergents, phonograph records, plastic toys, and toothpaste.
Although we use a huge variety of products made from petroleum, few people ever see the substance itself. Most of it comes from deep within the earth as a liquid called crude oil. Different types of crude oil vary in thickness and color, ranging from a thin, clear oil to a thick, tarlike substance. Petroleum is also found in solid form in certain rocks and sands.

The word petroleum comes from two Latin words meaning rock and oil. People gave it this name because they first found it seeping up from the earth through cracks in surface rocks. Today, petroleum is often referred to simply as oil, and most of it is found in rocks beneath the earth’s surface.

People have used petroleum for thousands of years. But few people recognized its full value until the 1800′s, when the kerosene lamp and the automobile were invented. These inventions created an enormous demand for two petroleum fuels, kerosene and gasoline. Since about 1900, scientists have steadily increased the variety and improved the quality of petroleum products.

Petroleum, like other minerals, cannot be replaced after it has been used. People are using more and more petroleum each year, and the world’s supply is rapidly running out. If present rates of consumption continue, petroleum may become scarce sometime in the mid-2000′s.

Most industrialized nations depend heavily on imported petroleum to meet their energy needs. As a result of this dependence, oil-exporting countries have been able to use petroleum as a political and economic weapon by restricting exports to some of these nations. Oil exporters have also strained the economies of a large number of countries, particularly the poorer ones, by drastically increasing the price of petroleum.

To prevent a full-scale energy shortage, scientists are experimenting with artificial forms of oil and with other sources of fuel. But even if new energy sources appear quickly, people will have to rely on petroleum for many years. Conservation of oil has thus become urgent for every country. People now need to be just as inventive in finding ways to conserve petroleum as they have been in finding ways to use it.