Sir P.A.M Dirac is considered as the greatest physicist in Britain after Newton. A stern father made him the man of few words. But this trait turned on an intense internal energy which manifested in the form of beautiful equations when he married Einstein’s relativity with quantum mechanism. On the basis of his research, he envisaged sub atomic particles which have equal and opposite electrical charge and equal mass to particles like electrons. His equations yielded two solutions like quadratic equations. Proof came soon when in a experiment in cloud chamber, a particle, hitherto, unknown was observed following mirror trajectory to the electrons emitted from a radioactive particle. It is clear that in a magnetic field, the particles follow a circular trajectory. So this particle was opposite of electron with equal mass. So his prediction was borne true. This particle is called anti-electron or positron. Soon, it became known that there is antimatter to every type of matter. In fact, now scientists believe that there exist space with antimatter and efforts are on to exploit their potential.
Another such great person was a Russian chemist. His name was Dmitri Ivanovich Mendeleev. At the time when he was on the scene, the concept of atomic number of elements was unknown. Only few elements were known to chemists. The physical parameter which was considered important for distinguishing the elements from each other was atomic weight. He was the first man to arrange the elements in groups based on their properties. His insight of the nature was so great that he left many blank places for elements which were not known then. He gave them names prefixed by eka, dvi and tri added to the element preceding the one with eka prefix. For example, ekaboron was the name of element which occupied next place to Boron. It was later discovered and is called Scandium. He had predicted all the properties of the element to be discovered and they matched almost exactly to the element when discovered. His periodic table is the forerunner of the modern periodic table which has evolved over time and is based on the atomic number concept. It is based on the premise that elements in a group have similar electronic configuration and all the elements fall in periods with elements in group having similar properties but increasing atomic numbers. Each element has an added shell of electrons to the previous one. Incidentally, prefixes eka, dvi and tri have been adapted from Sanskrit and mean one, two and three. This love for Sanskrit is said to be due to one of his friends being an Sanskrit scholar.