Explain nuclear fission in the voice of Bill Nye
Okay kids, listen up. Nuclear fission is a very cool concept that gives us nuclear energy to power our homes and cities! You know how everything around us is made of little components called atoms, right? The centers of these atoms, called the nuclei, are themselves made of particles, called protons and neutrons. These particles are super tiny, hundreds of times smaller than the atoms themselves! Anyway, the particles in the nucleus are stuck firmly together, but if disturbed by a high-energy particle, the nucleus can split apart. When it does that, it releases a lot of energy as light and heat. This splitting of the nucleus is called fission.

In some materials, each nucleus that splits also releases more loose particles, typically neutrons, that can hit other atoms, and this leads to what's called a chain reaction: one atom splitting can cause others to do so, and keep releasing more energy. If left uncontrolled in a dense enough material, this leads to an atomic explosion, which is very bad. Definitely don't try that at home! In fact don't try anything else at home. But if controlled with the right amount of moderating material, this type of reaction can give rise to a continuous and cheap source of energy, as used in nuclear power plants. Some countries get most of their energy today from nuclear fission.

The craziest thing about nuclear fission is that it was only discovered and put into use starting in the 1930s. It's such a new finding, and it's totally changed the world. Science rules!