Okay, kiddo, let's talk about neutrino mass. First, let me tell you what a neutrino is. A neutrino is a tiny particle that is so small you can't see it, even with the most powerful microscope in the world. It's even smaller than an atom!
Now, scientists have been studying these tiny particles for a long time, and they recently found out that some neutrinos have a little bit of mass. Mass is just a fancy word for how much stuff is in something. Like, you have mass because you have a body, and that body has weight because it's made of stuff.
Anyway, because neutrinos are so small, it's hard for scientists to measure how much mass they have. They had to do a lot of experiments to figure it out, and they're still not 100% sure, but they think that neutrinos have a super tiny mass.
This discovery is actually a big deal! It helps us understand more about the universe and the way things work. And who knows, maybe one day we'll find a way to use neutrinos to do cool things like travel faster than light or communicate across the galaxy. But for now, we're just happy to keep learning new things about them!