Oil grades explained
On this Wikipedia the language links are at the top of the page across from the article title. The general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure, properties, and uses. Oils may oil grades explained animal, vegetable, or petrochemical in origin, and may be volatile or non-volatile. Organic oils are produced in remarkable diversity by plants, animals, and other organisms through natural metabolic processes.
Lipids can be classified by the way that they are made by an organism, their chemical structure and their limited solubility in water compared to oils. Crude oil, or petroleum, and its refined components, collectively termed petrochemicals, are crucial resources in the modern economy. Several edible vegetable and animal oils, and also fats, are used for various purposes in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water.
Oils are applied to hair to give it a lustrous look, to prevent tangles and roughness and to stabilize the hair to promote growth. Oil has been used throughout history as a religious medium. It is often considered a spiritually purifying agent and is used for anointing purposes. Color pigments are easily suspended in oil, making it suitable as a supporting medium for paints. The oldest known extant oil paintings date from 650 AD. Oils are used as coolants in oil cooling, for instance in electric transformers. Given that they are non-polar, oils do not easily adhere to other substances.
This makes them useful as lubricants for various engineering purposes. Mineral oils are more commonly used as machine lubricants than biological oils are. Whale oil is preferred for lubricating clocks, because it does not evaporate, leaving dust, although its use was banned in the USA in 1980. It is a long-running myth that spermaceti from whales has still been used in NASA projects such as the Hubble Space Telescope and the Voyager probe because of its extremely low freezing temperature.
Some oils burn in liquid or aerosol form, generating light, and heat which can be used directly or converted into other forms of energy such as electricity or mechanical work. In the 18th and 19th centuries, whale oil was commonly used for lamps, which was replaced with natural gas and then electricity. This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Crude oil can be refined into a wide variety of component hydrocarbons.
