Soap is a solid, powder or liquid substance made with the purpose of cleaning the surface of some dirty material, and which is manufactured by cooking until it melts a mixture of vegetable or animal fats and oils.
The concern of the human being for the cleanliness of the body and its environment has always been known, that is why the manufacture of soap is one of the oldest chemical syntheses. For example, the Germanic tribes of Caesar's time boiled goat tallow with potash (potassium hydroxide) which they obtained by leaching from the ashes of a wood fire.
Modern chemistry has refined raw materials as well as technique, but soap making is basically the same as two thousand years ago: a fatty acid (of plant or animal origin) is combined with a solution of water and an alkali (sodium or potassium hydroxide) thus producing soap and glycerin, this reaction is known as saponification .
The fatty acids required to make soap are obtained from tallow, fat and fish oils. Soap can vary in its composition and in the method of its processing.
The hard soaps are made from oils and fats containing high percentage of saturated fatty acids, which are saponified with sodium hydroxide, and are used to wash objects and clothing. The soft soaps are produced with oil, linseed oil, cotton seed and fish oil, and saponified with potassium hydroxide, these are mostly the liquid soaps hygiene (shampoo, gel, soap and shaving foam, etc.).
Toilet soaps are made from vegetable oils such as coconut, palm, and olive. These oils are subjected to a refining process to remove the traces of caustic soda that they may contain, since they would damage the skin.
The dispersing power of soap allows it to eliminate the solid particles that constitute dirt, keeping them in suspension, in order to be able to be washed immediately by the water during the bath.
In general, soaps have evolved throughout history in different formats and varieties, they have even diversified in styles according to the characteristic of each skin and the needs it requires. Whatever the soaps, they do their job of cleaning dirt particles.
Nowadays, soap is also used as a bathroom decorator, there are different forms and decoration designs for it, some even have excellent fragrances to permeate the environment.
