David Ryan, age 12, of Toronto Ontario
What is nuclear fission?
The word fission comes to us from a Latin word meaning to split, Nuclear, of course, is something to do with nuclei or a nucleus. And nucleus comes to us from a Latin word for kernel, or core of a nut. The word nucleus was borrowed to name the central core of the atom. Nuclear fissions then$ is atom splitting ‑ the rending of the central core of the tiny atom.
It is no job to split off the outer particles of the atom. These are the electrons, the tiny mites of negative electricity, Electrons seem to be rather loosely attached' especially in certain atoms, A jolt of magnetism sends them chasing around a circuit of copper wire. We tap the wire to get electric power.
The particles in the nucleus however refuse to be budged by any jolt. Some are protons of positive electricity, some are electrically neutral particles called neutrons. Theses and maybe other particles$ are firmly bound together to form the nucleus of the atom.
We are not certain of the powerful energy that binds the particles of the nucleus together. It may come from the particles themselves. Each may turn a little of its mass into this terrific adhesive energy, . In any case it seems that a number of the free particles has a total mass slightly greater than the same number when packed into the nucleus.'
Whatever binds the particles together is a mighty powerful form of energy. Some of it is released when the nucleus is split in nuclear fission. Atoms can be split with atomic particles whipped to terrific speeds and fired. Protons have been used as these high speed bullets for atom sp1ttting. When one gets a bull's eye, a nucleus may split apart and release its energy. Most protons, however fall short of the mark. The nucleus is charged with positive electricity which tends to repel the protons which are also positively charged.
A neutron bullet has a better chance of reaching the nucleus of an atom. It is not repelled by the positive charge of the nucleus and may nestle its way among the tightly held particles. This may upset the delicate balance within the nucleus, causing its particles to break asunder: releasing some of their energy.
A neutron bullet usually finishes its job by splitting just one atom. Lots of power and complex machinery are needed to release the energy from just a few atoms by this method. But the chain reaction was discovered, particles from certain atoms turned themselves into more bullets that went on to split up more atoms.
Nature it seems, does this all the time with radioactive materials, A certain form of radioactive uranium was put to work splitting atoms by chain reaction. The first atomic bombs were made. This kind of nuclear fission can be tamed down and we‑look forward to the time when it can be used to give us everyday atomic power.