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Oil

physical science Maturity 11-13 Next article →

Oil is a liquid substance with many different uses in our world. It is defined as a nonpolar chemical substance made mostly of hydrocarbons. Because it is nonpolar, oil is hydrophobic, which means it does not mix with water. However, it is lipophilic, so it mixes easily with other oils. The thickness of an oil, known as its viscosity, can change depending on the temperature. Most oils are unsaturated lipids that remain liquid at room temperature.

Italian olive oil 2007
Italian olive oil 2007

There are several different types of oils based on how they are formed. Organic oils are produced by plants, animals, and other living organisms through natural metabolic processes. These oils contain lipids, which are fatty acids and steroids. They may also contain other substances like proteins or waxes. Another type is mineral oil, which comes from crude oil or petroleum. While the name suggests it comes from minerals, it actually comes from ancient organic materials like algae and zooplankton. Geochemical processes over a long time convert these fossils into oil deep underground.

Motor oil
Motor oil

Humans have used oil for many different purposes throughout history. The word "oil" has roots in ancient Greek, where "elaion" meant olive oil. In the 12th or 13th century, the Latin word "oleum" was used. In ancient Greece and Rome, people used olive oil for lighting. They also used it as a cleanser for their skin. Because oil is hydrophobic, it could pull grime to the surface of the skin. People would then use a wooden stick to scrub the oil and dirt away.

Italian olive oil 2007
Italian olive oil 2007

In the kitchen, oils are essential for cooking and food preparation. Edible vegetable oils come from plants like maize, sunflower, or olives. Animal fats, such as lard or butter, are also used. Many foods are fried in oil because it can reach much hotter temperatures than boiling water. Oils also help change the texture of food or add flavor. Some oils, like fish oil, contain omega-3 fatty acids. These specific acids can help reduce inflammation and fat in the bloodstream.

Oils also play a massive role in industry and energy. Crude oil is pumped from the ground and sent to refineries. There, it undergoes fractional distillation to become many different products. A single barrel of crude oil can be turned into diesel, jet fuel, gasoline, and heating oil. These products are used for transportation and heating. Petrochemicals, which are the refined components of crude oil, are used to make plastics, detergents, medicines, and synthetic rubber.

Motor oil
Motor oil

Beyond fuel, oils are used for lubrication and heat transfer. Because oils are non-polar, they do not stick easily to other substances. This makes them excellent lubricants for engineering and machinery. Mineral oils are often used to lubricate machines. In the past, whale oil was used to lubricate clocks because it did not evaporate. Oils are also used as coolants in electric transformers to help manage heat. Some oils are even used as a medium for paints, with the oldest known oil paintings dating back to 650 AD.

Finally, oil has deep connections to culture and science. Specially prepared oils are used in religious rituals as purifying agents. For example, holy anointing oil is important in Judaism and Christianity. In the world of science, organic oils are important for green chemistry. They serve as a chemical feedstock, which is a starting material for making other chemicals. From the food we eat to the fuel in airplanes, oils are a fundamental part of modern life and history.

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