Michael Brady, age 11, of Phoenix, Ariz., for his question:
What exactly is the meaning of nuclear physics?
The first nuclear physicists thought of themselves as chemists. The immense science of chemistry spreads into many fields of more specialized subjects. The study of the atom and the physics involved in its dynamic nature gave birth to the specialized science of nuclear physics.
The word nuclear refers to the nucleus of the atom, which is the dynamic core of the mighty midget. The word physics covers a multitude of science concepts that deal with matter and energy. A physicist depends on math to grasp and apply the laws of
Physics. A space scientist uses certain laws of physics to launch a satellite and plot its path. Chemists use laws of physics to rearrange molecules into new synthetics.
Builders and mechanics, electricians and engineers must base their work on the sound principles of physics. In fact, the many sided science of matter and energy is behind every practical project in our modern world. It is the master science of the age of sciencce. Its laws operate even in the miniature domain of atoms and molecules. And the nucleus of the mighty little atom confronted scientists with an entirely new concept of matter and energy. Former scientists thought that the atom was the smallest, undividable particle of matter and that matter and energy were forever different. But the atom has been split apart, and its shattered nucleus proves that matter is but a frozen form of energy. This is the realm of nuclear physics. Nuclear physicists can rearrange the particles of the atomic nucleus. Particles can be split from the nucleus, leaving a smaller atom of a different kind. Small atoms can be assembled into larger atoms.
The atomic nucleus is the tightest little fist in the universe. Its infinitesimal particles of matter are bound together by forces of nuclear energy. When the nucleus is changed, some of this energy is released and some of its matter is converted into energy. In nuclear fission, atoms are split apart into smaller atoms. In nuclear fusion, smaller atoms are built into larger atoms. Nuclear physicists use countless atoms to release staggering quantities of nuclear energy.
Some nuclear physicists specialize in astronomy. The stars are powerhouses of nuclear activity, and our sun performs nuclear fusion on a stupendous scale. Its small atoms of hydrogen fuse to form larger atoms of helium. Fragments of matter left over from the fusion process are converted into nuclear energy and released. The energy of an atomic bomb comes from nuclear fission in which atoms are split into smaller atoms. The energy of a hydrogen bomb comes from nuclear fusion, somewhat similar to the sustained nuclear activity of the sun.