I'm making this really simple. If you want to learn more, I've linked the necessary Wikipedia articles.

So, imagine you have a group of atoms attending a party. These atoms (primarily uranium) are jumping around and having a blast. But there are some mischievous atoms known as neutrons. They're the troublemakers, and they crash into this party (literally) and start a chain reaction.

These troublemakers (neutrons) crash into the uranium atoms at high speeds, causing them to split. This splitting releases an immense amount of energy, just like those party poppers that launch confetti everywhere. The uranium atoms breaking in half release more troublemaker neutrons, which then crash into more uranium atoms and keep the party going.

But things can get out of control if we don't keep things cool. So, in comes the chill factor – a coolant. It's like a cool drink that cools down the party and assures that things don't heat up too much. Now, we need a DJ to create the right atmosphere, and that's where a control rod comes in. These rods can absorb the troublemakers (neutrons) and regulate the intensity of the chain reaction (fission reaction). They're like the bouncers at a bar, ensuring things don't get too rowdy.

And that's how a nuclear reactor works.