By: Tony Wang
Ever since the beginning of the COVID-19 pandemic, people have constantly been saying that it is imperative that one washes their hands with water and soap. However, what exactly does this do in terms of hygiene? Well, the water part is self-explanatory; it washes off the dirt and dust on your hands. But what exactly does the soap do?
Our hands contain many natural oils, and because of this, it is very easy for germs to get stuck on our hands. And since water and oil don’t mix, simply washing our hands with plain water cannot get rid of these dangerous pathogens. Our ancestors knew this, and as such, knew that they needed to develop something that could get rid of these pathogens. And what they came up with was soap.
Some of the earliest forms of soap were discovered thousands of years ago. These versions of soap were created when people discovered that certain substances could wash materials better than plain water. The Babylonians, for instance, started making soap around 2800 B.C. They did this by boiling the fat of animals with ashes. This soap was not only used in textile manufacturing, but was also used medicinally. There are multiple other examples of ancient societies developing their own versions of soap. The ancient Egyptians mixed animal oils and vegetable oils with alkaline salts to produce a soap-like substance while The Phoenicians used goat's tallow and wood ashes to create soap in 600 B.C. Even the Romans made soaps from urine.
Now, let’s talk more about soap itself. As stated previously, most soaps are made from fat, also known as oil. Oils are, essentially, fats composed of molecules that have a polar, salty “head” on one side and a nonpolar, fatty “tail” on the other side. When someone applies soap to their hands, the soap’s fatty tail faces the grime, whereas its head faces the water. But it isn’t just one soap molecule that does this; there are actually dozens of different ones! All of these soap molecules come together, with their tails facing the grime and their heads facing the water. By doing this, they form a circular structure known as a micelle. The micelle sweeps the dirt away, one particle at a time, effectively removing them from the object. However, this doesn’t actually destroy the microbes; it just removes them from the area. This is why it is so important to make sure you wash all the soap off your hands with clean running water.
Now, when soap was initially created, it wasn’t very popular. However, as time went on, and people’s understanding of the role of proper hygiene improved, soap became more and more popular. This, in turn, resulted in the development of industrially manufactured bar soaps in the late eighteenth century. Nicholas Leblanc, a chemist, was responsible for this. He patented a method of making sodium carbonate, one of the main ingredients of soap, from commonly available salts. By introducing such a simple way to produce soap, Nicholas Leblanc made it so that soap could be industrially manufactured. However, the commercial soap we know today only came into existence during WWI. After the Great War and until 1930's, a method called batch kettle boiling was used for soap production. Shortly after, a process that built on this method by decreasing soap production time to less than a day was introduced and refined by Procter & Gamble. This process is still used by large commercial soap manufacturers today.
Overall, thanks to the early discovery of soap, humans have been able to prevent countless diseases, and soap continues to be a silent hero fighting on the front lines of human health and wellness. And during the current pandemic, the importance of soap is clearer than ever.
What Did You Learn?
Questions:
1. How did people in the past use soap?
In the past, soap was actually not used for bathing by most commoners. Instead, it was usually used to wash cloth in textile manufacturing sites. At the time, only wealthy individuals such as rulers and nobles used actual high-quality soap to bathe themselves. Although these soaps were not as effective as modern soaps, they could still help people improve hygiene. These soaps were often also infused with specific flowers to carry fragrances.
2. Why does the fatty tail face the grime?
Grime is created from the body’s natural oils, which are nonpolar molecules. Since nonpolar molecules attract each other and polar molecules attract each other, the nonpolar molecules naturally attract the nonpolar fatty tails and the salty polar heads naturally attract the polar water. This allows the soap to effectively remove the grime from the object.
Citations:
Image Credit:
No changes were made to the following image, https://flic.kr/p/7JK2Uq, License: https://creativecommons.org/licenses/by-sa/2.0/legalcode
No changes were made to the following image, https://flic.kr/p/JBadHT, License: https://creativecommons.org/licenses/by/2.0/legalcode
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