Ok kiddo, imagine you're playing with your toy car and you accidentally spill some juice on it. Now imagine your car is a really big car and the juice is fuel.
A fuel leak happens when the fuel that is supposed to stay inside the car's tank, engine or pipes starts coming out where it shouldn't. This can happen for different reasons, like when the car is not working properly, the fuel tank is damaged or the pipes that transport the fuel are broken.
When the fuel leaks out, it can be really dangerous. Fuel is flammable, which means it can catch fire easily. If the fuel gets on hot parts of the car, like the engine or the exhaust system, it can ignite and cause a fire.
That's why it's very important to fix a fuel leak as soon as possible. If you ever see or smell fuel on the ground or in the air around a car, tell a grown-up right away so they can take action to stop the leak and keep everyone safe.