Many a times you must have experienced in your life that you cannot recall a certain incident, name of a person or a book or author although at other times you remembered it so well. In those circumstances, the harder you try to recall more it eludes you. It is not the case of poor memory or age as it happens with everyone at one time or another. You leave it frustrated and become busy in some other work and in a flash the things will come to your mind. The same has happened to many great scientists and authors.
August Kekulé von Stradonitz, the great chemist who elucidated the structure of benzene did it in reverie while riding a horse drawn bus. As he will doze off, he saw the atoms dancing before his eyes. These atoms caught hold of each other. The bigger ones held more than one smaller atoms and so on. Thus he was able to arrive at the ring structure of the benzene molecule. Not only that, he was able to draw the structure of molecules with same molecular formula but different physical properties. He was talking about geometrical isomers.
It was left to his brilliant young student Vant Hoff to discover the sterochemistry of carbon molecules in which different groups are attached to a carbon atom. Such carbon atoms are said to be asymmetric and stereo isomerism imparts a property of deflecting light to right or left from its path when light travels through the solution of such substances. Such molecules display optical activity with dextro (right) rotatory and levo (left) rotatory categories.
Whenever such compounds are synthesized in the laboratory we end up with 50:50 mixtures of both forms which are optically inactive because the deflection caused by one set to left is countered by another set to the right. To separate these mixture into pure forms, these mixtures are reacted with a pure levo or dextro rotatory compound resulting in two salts of different melting of boiling points which are easily separable. After separation the add on molecule has to be detached to obtain the pure compound of levo or dextro nature. n nature, we encountered only single type of compounds either levo-rotatory or dextro rotatory because most of the natural compounds are synthesized by different routes using the enzymes.
It was the great Luis Pasteur who separated the two optically active forms of tartaric acid crystals using tweezers and demonstrated the optical activity. The weather of France also assisted him because the tartaric acid obtained from the raw grapes formed large beautiful crystals.
Another example of great achievements of wandering mind is that of Greek mathematician Archimedes. He was given the commission by the King to know whether the crown he ordered to be made was really of Gold or of gold alloy. Archimedes thought and thought about solving the problem from many angles but was frustrated and he decided to leave aside the problem for sometimes. He ordered his servant to make a bath for him. As he lowered himself into the bath, he saw the level of water rising. The idea that same weights of different elements displace the different volume of water suddenly flashed to his mind. This way he can find the volume that a certain weight of gold will occupy perhaps by comparing the crown weight by same weight pure gold. He was so elated that he jumped out of the bath and ran naked towards the palace shouting the now famous word “Eureka”