Making materials we can use
Yasmin Jayathirtha
I hope you enjoyed the special issue on chemistry. There were a lot of articles that described the modern chemicals and processes. Many authors wrote about their enjoyment of the subject and what hooked them to it – a magical colour change or an explanation of a phenomenon. I like the subject and I date my interest to the time, when, after a class on acids and bases, I washed a haldi stain off my white uniform blouse and recognized the colour change as an indicator colour change. This interest has continued and the fact that I can explain many reactions in daily life is a large part of the fun.
I have often wondered how people long ago made and used new materials. What did they observe? How did they recognize uses, say, of medicinal plants? When and how were the chemicals of general use made? Consider personal hygiene – cleaning agents have been used for a long time. They have been sourced from nature; shikkakai, reetha, neem twigs, hibiscus flowers, multani mitti… Every culture has similar cleaning agents. What observations led to these being picked? Toothpastes/powders and soaps are really ancient. Soaps were made in the Middle East about 4500 years ago. In the 4th century BC, Hippocrates advocated the use of ground marble for cleaning teeth. Many toothpastes still have a base of calcium carbonate.
Using materials available in the surroundings is one thing. It requires keen observation and experimentation as to their use. But making new chemicals like soap, a chemical reaction involving oils and fats and an alkali like sodium/potassium hydroxides or carbonates, who worked it out? How? What led to a usable material? We can buy these chemicals, but in earlier times they were extracted from wood ash. So there must have been a very determined person who worked at it. A series of books called 'Earth's Children' written by Jean Auel, set in prehistoric Europe, details the possible ways some of the discoveries could have been made. It is very interesting, but I am still awed by the magnitude of the work that went into it.
We will make two common items of personal use, toothpaste and soap.
The author works with Centre for Learning, Bengaluru. She can be reached at [email protected].
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August 2013, Let's Experiment!