Soap

Sometimes I wake up thinking about such things...

How Soap Works

Soaps are useful for cleaning because soap molecules attach readily to both nonpolar molecules (such as grease or oil) and polar molecules (such as water). Although grease will normally adhere to skin or clothing, the soap molecules can attach to it as a "handle" and make it easier to rinse away. Applied to a soiled surface, soapy water effectively holds particles in suspension so the whole of it can be rinsed off with clean water. The hydrocarbon ("fatty") portion dissolves dirt and oils, while the ionic end makes it soluble in water. Therefore, it allows water to remove normally-insoluble matter by emulsification.

The History of Soap
The earliest recorded evidence of the production of soap-like materials dates back to around 2800 BC in Ancient Babylon.[1] A formula for soap consisting of water, alkali and cassia oil was written on a Babylonian clay tablet around 2200 BC.

True soaps made from vegetable oils (such as olive oil), aromatic oils (such as thyme oil) and Lye (al-Soda al-Kawia) were first produced by Muslim chemists in the medieval Islamic world.[3] The formula for soap used since then hasn't changed. From the beginning of the 7th century, soap was produced in Nablus (West Bank, Palestine), Kufa (Iraq) and Basra (Iraq). Soaps, as we know them today, are descendants of historical Arabian Soaps.

From "Soap" in Wikipedia.