What is a Nuclear Reaction?
The nucleus of every atom is composed of nuclear particles, or nucleons: positively charged protons (p⁺) and neutral neutrons (n^o). A nuclear reaction occurs when you add or subtract a nucleon to a nucleus.

The Forces of Nature

• Gravity is the force that keeps the Earth forever falling around the Sun, the Moon circling above us, and all of the people in this room firmly in their seats. Gravity also prevents the Sun from expanding in size, despite the fact that it is made up of hot gas. It is an attractive force between objects with mass.

• Electric Force is a force felt between charged particles such as electrons (e^-) and protons (p⁺). There are both attractive and repulsive electrical forces. When charged particles interact, like charges repel, and opposite charges attract (think of magnets). The electrical force holds atoms and molecules together, and controls much of the technology developed over the last 150 years.

  The electric force is also what keeps you from falling through your chair, through the floor, and through the Earth, and being baked to a crisp at the Earth's core. You are held suspended above your chair by the repulsive force of the protons in your body working against the protons that make up your chair.

• Nuclear Force: one could argue that the nuclei of atoms which contain protons and neutrons should not be stable. All those like charged protons should be repelling one another, and flying right out of the nucleus. Since nuclei are stable, it can be inferred that there is another force that is stronger than the electrical force, one which glues those nuclei together. This is the Nuclear, or Strong Force. The nuclear force would bind everything together, except for the fact that it acts only over very tiny distances.

There are two paths to deriving energy from nuclear reactions – fission and fusion.