Accidental Inventions
D. Indumathi, The Institute of Mathematical Sciences, Chennai

Many discoveries in Science happen accidentally: when the person observing some mundane or everyday activity suddenly gets an unusual idea about how things work. Some of these discoveries help us understand our Universe better, while some discoveries lead to new inventions that make life more convenient or comfortable.

How heat makes things stronger
It was the year 1839, about 180 years ago. Rubber had been used by man for thousands of years--the Aztecs had known the uses of the natural rubber tree from 1600 B.C. At the time we are talking of, it was used to make footwear and other things such as waterproof raincoats but it was not very reliable.
Charles Goodyear in the US was trying to make rubber more durable, so it would not melt in the heat of summer. He tried various things but was not very successful. One of the things he tried was to mix rubber gum with sulphur so that it was less sticky. One day when demonstrating his product to a shop-owner, he accidentally dropped his rubber-sulphur mix on a hot stove.
Surprisingly, the rubber did not melt, but charred black. This tough substance was more useful in that it did not melt in summer and could be made into whatever shapes were required. The process was called vulcanisation and it began the huge vulcanised rubber tyre industry: till today, vehicle tyres are made of vulcanised rubber. That's why your bicycle tyres don't melt even on a hot summer's day!

How to be untidy ... and lucky
It was the year 1928. Alexander Fleming was a scientist working on a Petri dish full of Staphylococcus bacteria in his lab in Sotland. He was trying to find some chemicals that would kill the bacteria, but had not succeeded. Then he went awaty on vacation, without cleaning up the lab, or emptying the dish of bacteria. On top of all else, he also left the lab window open.
When he came back, he found that some pieces of common mould (the grey stuff that grows on old bread) had been blown in through the open window. Some of it was growing in the Petri dishes.
Being observant Fleming noticed something curious: where-ever there were spots of mould no bateria was growing. That is, something in the mould had killed off the bacteria. Fleming called this substance Penicillin and this was the beginning of the discovery of such Anti-biotics which are so commonly in use today.
Fleming did not actually succeed in isolating or making enough penicillin to cure people; that had to wait another ten years and for contribution from other scientists. It was only after the seocond world war that there was enough penicillin manufactured to treat common people, but Fleming is still considered the father of anti-biotics. Not only was he untidy and lucky, but he was a good observer and that made him a good scientist!

Lessons from the Burdock plant
George de Mestral was walking his dog one day in the mountainous Alps in Switzerland in 1941. Daily he noticed that some bur from the burdock plant was sticking to his dog's fur. In fact, it took him a long time to remove these burs. You must also have had occasions when some particularly thorny plant or seed has stuck to your socks and you may have had difficulty in pulling it off. 
However, de Mestral looked at things differently. He was curious about what mechanism caused the bur to stick on so strongly to the dog's fur that he had to struggle to get it off. 
Looking at the bur under the microscope, he found that the pointed ends of the burs actually were bent around like the handle of an umbrella (See picture). So if you tried to pull them off, they would grip even tighter and become difficult to detach. de Mestral pondered over this discovery for some time. Then he realised that this phenomenon could be coverted into a very practical use ... and velcro was born!
This is exactly how velcro functions: one strip contains a lot of furry hair-like material that can easily get trapped. The other side has tiny little bur-like hooks that can grip the hair-like material. While de Mestral used cotton material initially, now-a-days it is made of nylon. This lasts longer than cotton and the "hooks" also keep their shape longer.
So, next time you see someone putting on their shoes in a jiffy using velcro, rather than having to tie their shoelaces, remember de Mestral and his curiosity!
Many such discoveries have led to useful inventions; some have even been fun: invention of cone ice cream, chocolate chip cookies, cornflakes, and potato chips in food, and toys such as slinky, play-doh, silly putty, or useful things such as cellophane wrappers and post-it notes, have all been made by accident.
In each instance, it must be remembered that the disovery was made because the person who made the discovery was observant and came to the right conclusions about what had been observed. So chance is not enough: apart from being lucky, you must observe keenly. Next time you make a discovery for yourself, write to JM and tell us about it!