All things – even you – are made up of billions and billions of “bits” that are smaller than anything you can imagine. These “bits” are called atoms. Atoms are the tiniest parts that something can be broken into and still be the same stuff. For example, one atom of gold is the tiniest bit of gold possible.
Special machines can split certain kinds of atoms into even smaller parts. When atoms split, they give off energy. The part of the atom that splits is called the nucleus, so the energy is called nuclear energy.
The energy given off by atoms when they are split is in the form of heat. So a machine that splits atoms can be used the same way a fuel-burning engine is used. The machine makes heat. The heat can be used to run generators that make electricity and to run other machines, too.
Picture Credit : Google