nuclear energy
The large amount of energy released from the nucleus of atoms is known as nuclear, or atomic, energy. The nucleus is the dense central part of the atom, the smallest unit of matter.
Nuclear energy is released from the nucleus of atoms either by fission or fusion. Nuclear fission occurs when a nucleus splits into two or more parts. Nuclear fusion occurs when two nuclei join to form a single nucleus. The nuclear energy released by the fission or fusion of nuclei is in the form of radiation. Radiation is the transmission, or spreading, of heat, light, and sound waves.
In the 1930s scientists discovered that it was possible to split the nucleus of the element uranium into two by bombarding the uranium with particles called neutrons. The scientists also discovered that during the fission process a large amount of energy is released. For example, when 1 pound (0.5 kilogram) of uranium undergoes a fission reaction, it produces energy equal to that released by the burning of 3,000 tons of coal.
Nuclear energy can be put to a wide variety of uses. Since nuclear energy was discovered during World War II (1939–45), many efforts were made to produce weapons that would use the explosive energy. The atomic bomb was one such device. The first atomic bomb was dropped on the city of Hiroshima in Japan on August 6, 1945. It destroyed most of the city and killed more than 70,000 people.
In more recent times, however, nuclear energy has been used for peaceful and constructive purposes as well. For example, it is used to create electricity in many places around the world, including the United States, through nuclear power plants. In addition, the energy produced from uranium is used to power submarines and other naval vessels. The field of medicine has benefited greatly from nuclear energy. Doctors make use of radioactive elements to locate lumps or swellings in the human body. This enables them to diagnose and treat patients suffering from abnormalities of the thyroid gland, cancer, and other diseases.
Nuclear energy has its drawbacks as well. It is very harmful to humans, animals, and plants and can bring about ill effects that could last for a lifetime or even many generations. Excessive radiation results in fatigue, nausea, loss of teeth and hair, and damage to the blood in humans.
Nuclear power plants are designed and operated with an emphasis on safety. Nevertheless, accidents at these plants are possible. A major accident occurred in 1986 at a nuclear power plant at Chernobyl in Ukraine. Harmful gases leaked out into the air and spread over much of Europe. These radioactive gases ruined crops and livestock and caused harm to many people. After this episode, steps were taken to prevent similar disasters in the future. Another difficult problem of nuclear energy is how to dispose of nuclear waste so that it does not spread into the environment. Until these drawbacks are solved, people will have to decide whether the benefits of using nuclear energy outweigh the risks.
