soap--could someone explain to me why it is needed with water, the science and the history of it?

Question

I am curious about soap. How is it that early man learned of its significance, what it was made of then, what it is made of now, why it is needed to obtain cleanliness that water alone cannot do

Answer 1

The earliest known evidence of soap use are Babylonian clay cylinders dating from 2800 BC containing a soap-like substance.

Soaps are useful for cleansing because soap molecules attach readily to both nonpolar molecules (such as grease or oil) and polar molecules (such as 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.

Answer 2

Soap is a wetting agent. Soap films (skins of bubbles) form because the soap and water molecules can form a thin sheet (one or more layers thick that can thin to a single layer) where the molecules attract (hang onto) each other and are directional (like people standing in a room). The "heads" of the molecules have an electronic charge and if they surround and coat a (dirt?) particle the particle will behave as though it had a very strong electronic charge repelling like (other dirt) particles and the cloth or hands that are also coated with a soap film. That allows the particles to remain suspended in water until rinsed away. The leaves (or other parts ) of certain plants when crushed in water can make soap bubbles which perhaps was mankind's introduction to soap.

Answer 3

In effect soap makes water wetter.