Until World War II, the world was familiar with only mechanical, chemical, acoustic, thermal, optic, magnetic and electrical forms of energy. But on a fateful day in 1945 when the U.S. exploded atom bomb over Hiroshima, the world got aware of nuclear energy.
How exactly is energy got from the atom? For the atom, as we know, is the tiniest speck of matter? Each atom has a central core called the nucleus, around which revolve the electrons. The nucleus is built up of two kinds of very minute particles called protons and neutrons. The electron has a negative electrical charge, the proton has an equal positive charge and the neutron has no charge.
The nucleus of the radium atom constantly disintegrates ejecting alpha particles which are the nuclei of helium atoms. This phenomenon is called radioactivity. Uranium is another radioactive element. In 1938 Hahn and Strassman bombarded uranium with neutrons and found traces of barium in the material.
This led to the discovery that some of the uranium atoms capture a bombarding neutron and get split into two nearly equal parts. This splitting is called nuclear fission. At the same time two or three neutrons are set free in the reaction. These go on splitting other uranium atoms and release neutrons. This is called a chain reaction and, in its wake, enormous amounts of heat and gamma rays which are X-rays of very short wavelength and great penetrating power are released.
This knowledge was utilised in the preparation of the atom bomb. Such a weapon had become imperative in view of the mounting supremacy of the Germans and Japanese in the World War. After three years of intensive work atom bombs were perfected. It is now history that the two atom bombs dropped on Hiroshima and Nagasaki knocked out the striking power of the enemies and brought the war to a speedy end. The two cities were completely destroyed with great loss of life. Such was the destructive power of the atom bomb. The energy needed was derived from nuclear fission.
The bomb demonstrated that nuclear fission provided a new and powerful source of energy and that it might be put to peaceful uses as well. In agriculture, atomic energy is used in the shape of radioactive tracers in researches for finding the best type of fertilisers for plants. In medicine, radioisotopes of iodine are used for diagnosing brain tumours. Other radioactive isotopes are used for the cure of the human ailments-in the treatment of cancer, radio-gold, radio-iodine and radio-cobalt. In industry, radio isotopes are used for measuring the thickness of paper, rubber, textile and metallic sheets, for the detection of hidden flaws in castings, for the detection of the thickness, flow and separation of liquids.
Nuclear energy is used vastly in the development of atomic power. When the supplies of coal and oil are running low, the development of atomic power is a welcome achievement. Nuclear energy offers a new source of cheap fuel for the production of power, especially in spots far for power production. The first step in the production of atomic power is the setting up of atomic reactors.