Michael Stack, age 13, of St. Catharines, Ontario, for his question:
What is the energy from radioactivity?
Radioactive energy comes from the mighty little atom, It is the power which is normally locked in the nucleus, the very heart of the atom. The particles of an atom are very strongly bound. together and it is no easy job to split them apart. This means that tremendous energy is used to hold them together. When a nucleus is broken apart, some of this energy is released.
Every atom is put together like a miniature solar system. The nucleus plays the role of the sun. Around it, like planets orbiting the sun, whirl the electrons. It is no hard job to strip electrons from an atom. We do it to make electric power. The atom which loses an electron tries to capture another. This does not change or upset the nucleus.
We usually find out how to use a force of nature before we fully understand. it. For example, we were using electricity long before we had any idea what it was. The same is true of our dealings with atomic energy. We know how to release energy from the atomic nucleus in two ways, by fission, which is atom splitting and by fusion, which is making atoms into larger ones. But there is still a great deal about the energy within the nucleus of the atom that we do not know.
We know about several different particles within the nucleus. But still more are waiting to be discovered and we have still much more to learn about the atomic glue, the tremendous energy which binds the particles of the nucleus together.
The way we have learned and are still learning is by study of radioactive materials. A substance is radioactive when its atoms of their own accord break apart into smaller atoms, Some of these substances are man‑made. Uranium is a radioactive substance found in nature. It seems that certain very large atoms tend to get top heavy. Then their nuclei break apart. Some of the particles and some of the energy which bound them are no them are no longer needed, They are given off as .radioactive energy.
Radioactive energy is given off as rays, which is why it is called radioactive. By studying these rays we have learned a great deal about the energy within the nucleus of the atoms.
Three types of energy ray pour forth from any radioactive material, They are called alpha rays, beta rays and gamma rays, named from three letters of the Greek alphabet. Rays of alpha particles move out at speeds up to 20, 000 miles a second. They are stopped by a sheet of paper or by a fraction of an inch of air. Rays of beta particles travel with almost the speed of light. The beta particles can travel through about a quarter inch of aluminum. The third and most energetic group of rays are of gamma particles. These energetic particles can penetrate six inches of lead or a whole foot of iron.