To understand how soap works, one has to look at an individual soap molecule composed of carbon, hydrogen, and oxygen. It has a "head" composed of carboxyl that attract water and a hydrocarbon "tail" that is hydrophobic (afraid of water) but loves oil and grease.
| A soap molecule's head is attracted to water, while its tale is attracted to the oil on your skin. |
You may have noticed that when you first step into the shower, water beads on the surface of your skin. This is because the surface tension of the water prevents it from reaching and clinging to the skin. When soap is introduced, the hydrophobic end of the soap molecules tries to get as far as possible from the water, while the water loving end of the molecule is attracted to the water. The result is a film that breaks the surface tension of the water allowing it to stick to the skin.
Now that the water and soap can reach your skin, the molecules enter phase two of the cleansing process. The pores of your skin secrete oils that create a barrier to protect you from the environment. This layer of grease traps dirt, dust, and other matter that makes us "dirty". When the oil and grease loving tail of the molecule comes in contact with the skin, it attaches itself to the oily layer containing the impurities. Once water is applied to rinse, the water loving head of the molecule literally pulls the dirty tails off the skin, leaving you squeaky clean.
For many people, the removal of the skin's oily layer can lead to irritation and itchiness. Harsh chemicals and synthetic fragrances can magnify this problem even more.
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