How is energy obtained from atoms?

There are a lot of strong forces in the nuclei of atoms, which keep the particles together, There are two ways to release the energy hidden in the atomic nuclei. We can fuse them with one another, as occurs in the core of the stars, or we can split them, which is done in at nuclear power plants. To split an atom to release energy, a chain reaction is required in a reactor. Many people consider the atomic power plants also called nuclear power plants dangerous because radioactive material is released in this process.

What force keep the atomic nuclei together?

Atoms are made up of  nucleus and a shell of electrons. The nucleus contains protons and neutrons. The protons are positively charged and repel each other like magnetic poles. At the same time, there is also a strong force of attraction, the nuclear force. This force prevents the  nuclei from flying apart. The origin of this force is complicated and nuclear physicists have been studying this phenomenon.

What is radioactivity?

Radioactivity is a property of the atomic nuclei to decay and thereby release radiation. Many atoms split when they are bombarded with neutrons, and others decay spontaneously. In both the cases, the radiation of radioactive material takes place. This radiation occurs in three forms. The alpha rays can reach only up to a few centimeters. The beta rays are made of electrons resulting from the splitting of atomic nuclei. They can go up to 1 m and are stopped by metallic foils. The gamma rays are bundled energy released in the decay and are very dangerous. Even thick lead plates can only partly stop them. They can penetrate the cells of our body and can modify or destroy them.