Soap

From Wikinfo

[[es:jab�n]]

Soap and detergent are substances for cleaning. They come in bars, powder and liquid form.

Soaps are mixtures of sodium or potassium salts of fatty acids which can be derived from oils or fats by reacting them with an alkali (like sodium or potassium hydroxide) at 80�-100 �C in the process known as saponification. Hydrolysis of the fats and oils occurs, yielding glycerol and crude soap.

Before commercially produced lye was common place, lye was produced at home for soap making from the ashes of a wood fire.

Although the soap term continues to be used informally in everyday speech and product labels, in practice nearly all kinds of "soap" in use today are actually detergents, which are less expensive, more effective, and easier to manufacture.

Soaps are useful and used primarily for cleansing because soap molecules attach readily to both non-polar 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.

The ancient world was generally innocent of soap; the Romans built baths, but did not often use soap in them. According to Pliny the Elder, soap was invented by the ancient Gauls. They did not use it for washing, though; they used it as a pomade to keep their hair shiny.

Historically, soap was often made in the home by mixing animal fats with lye. Because of the caustic lye, this was a dangerous procedure (perhaps more dangerous than any present-day home activities) which occasionally resulted in serious chemical burns or blindness.

One can play with soap by making soap-bubbles that float in the air.

See also: