Oil, which is also known as petroleum, is a slick and slimy black and sometimes yellow substance that is used by people for a lot of different things. In many cases, it is used to make gasoline for cars to run on, but it is also used in ink, crayons, tires, eyeglasses and DVDs!
Where does it come from? Petroleum is hidden underground in pockets of the Earth called pores. Fuel companies get to it by actually drilling holes in the ground and pumping the oil out. The petroleum wasn’t always there though. It was made over millions of years. It might be hard to believe, but it is actually made from ocean plants and ocean animals that lived and died millions of years ago! These plants and animals were buried under layers of sediment, which is just a big word that means “dirt and rocks and dust that build up over time.” Being trapped under thick layers of sediment causes a lot of pressure and heat to build up.
That heat and pressure causes the chemicals in those plants and animals to cook! Without air, they could not rot, and after millions of years, they became petroleum that people have discovered in the ground.
The oceans from millions of years ago were very different from today’s oceans. Many parts of the United States that are dry land today were flooded with ocean water hundreds of millions of years ago. That’s why oil can be found on dry land today.
The five countries that produce the most petroleum are Saudi Arabia, Russia, the United States, Iran, and China.