What is the weak force ?

The weak force is the least observed force. The weak force is involved with radioactive things. Like the strong force, it's range of interaction occurs over a very small distance (0.0000000000000001 m or 1 x 10-16 m) inside atoms.

The weak force normally applies to big, heavy atoms on the atomic scale (yet the atoms are not big enough to see). What happens is that the strong force can only cover a very tiny small area the normal size of an atom's nucleus. When the nucleus gets too big, the strong force cannot hold the nucleus together because of the repelling like charges inside the atom (the positive protons). Then, the weak force causes the atom to break up into smaller atoms and particles releasing electromagnetic energy. Some of the atom's mass has been transformed into energy. Such a reaction is known as a nuclear chain reaction.

Once the atoms are broken apart, the strong force can take control again and keep those atoms together. But sometimes, this process can take a very long time and some of the particles or gamma rays that they give off are harmful to humans.

Because some of the particles are so small and energetic that they penetrate your body and do strange things to it such as breaking bonds in atoms and molecules or changing the properties of cells if exposed long enough. It is interesting to note that the inhabitants on Earth are constantly being exposed to this same radiation on a daily basis. Earth's energy source, the sun, is constantly showering the inhabitants of Earth with very low levels (doses) of high energy radiation. Although not commonly accepted at this time, a study exists that actually indicates that low doses of high energy radiation may actually be healthy. For high energy sources, people on Earth warn other people with signs containing special symbols such as this radiation warning sign.

What is a gamma ray or gamma radiation ?

Gamma radiation, alpha radiation, beta radiation , and positron emission are all different types of particle or energy radiation. The energy given off by gamma radiation is commonly called a gamma ray. Energetic alpha particles (helium nuclei) are released in alpha radiation and energetic electrons are emitted in beta radiation. These particles or energy may be emitted from atoms during nuclear chain reactions.