Francine Graff, age 13, of Bartlesville, Okla., for her question:
HOW DOES SOAP WORK?
Soap, until recently, was the only washing agent we had. Now available also are many synthetic detergents which are actually soapless soaps.
Did you realize that nothing like soap can be found in natue? Before we learned to make soap, cleaning was done with oil, ashes, sand or pumice.
Soap was first used as a washing agent by Galen, a Greek physician from the second century A.D. Then the Italians in the seventh century made a yellow soap from potash and animal oils. The potash was obtained from lye, an alkalineliauid made by dripping hot water through wood ashes.
During the eighth century the Spanish made soap with olive oil replacing animal fat. The soap was called Castile, and it is still made today. During the ne t few centuries the French and the English also bean making soap, using fats and an alkali obtained from seaweed.
Among the first to settle in America were professional soapmakers. Though commercial soap was available by the 1800s, many American housewives made their own, using the same methods from several centuries earlier.
Soap molecules act in strange ways: one part of each molecule is attracted to water but repelled by dirt and grease, while the other end of the same molecule is attracted to dirt and grease but repelled by water. Part of the molecule tries to get deep into the water, while part tries to stay out. Both are evenly matched so instead of getting under the water or out of it, the soap stays right on the surface.
In doing the laundry, soap helps water get into every clothing fiber, including those beneath grease spots. It helps water get into grease by actually making the water wetter.
Soap Also loosens dirt and grease fragments from whatever is being washed. The soap coats each particle with a slippery film that prevents the particles from re forming into clumps. It also floats away the particles and keeps them suspended in the water.
After its cleansing action has workedg soap must be rinsed out of the washed articles, leaving behind neither dirt nor soap. Synthetic detergents perform this last task better than soap does.