Zero-point energy

Imagine a big empty box. When you look inside the box, you can't see anything, but that doesn't mean the box is completely empty. Even if all the air molecules were removed, there would still be some energy in the box. This energy is called "zero-point energy."

To help you understand what this energy is, imagine you have a toy car that you wind up and release. As the car moves forward, it slows down because the energy you used to wind it up is being used up. But even when the car has stopped moving, it still has some energy left. This energy is called "kinetic energy" and is why the car doesn't move on its own.

Similarly, when you take all of the energy out of the box, there is still some energy left. This energy is the zero-point energy. It comes from the fact that empty space isn't really empty at all. It's full of tiny particles that pop in and out of existence, appearing for just a fraction of a second before disappearing again. Scientists call these particles "virtual particles."

Even though these particles don't stick around for very long, they still have energy in them. This energy adds up, and that's why there is zero-point energy in the box.

Scientists are very interested in zero-point energy because it has the potential to provide a source of limitless energy. But it's still a very new and complicated concept, so even the smartest scientists are still trying to figure it all out!