What are nonequilibrium systems?

A nonequilibrium system is like a group of kids who are all running around on a playground, they're not settled or calm at all.

Imagine you have a jar full of jelly beans. If you shake it really hard and then stop, the jelly beans are all jumbled up and moving, that’s nonequilibrium. But if you let it sit for a while, eventually the jelly beans will settle down into a nice even layer, that’s equilibrium.

Think of a playground at lunchtime. Kids are running, laughing, sliding, and playing, they’re all over the place. That's like a nonequilibrium system because everything is moving around and changing. But if it gets quiet and everyone sits down to eat, that’s like reaching equilibrium, things are calm and not changing much.

A boiling pot of water is also a nonequilibrium system. The bubbles are popping up all over the place, and the water is moving around, it's not settled at all. But when you turn off the heat and let it cool down, eventually it will stop bubbling and become still again, that’s equilibrium.

So, nonequilibrium systems are just like a busy playground or a boiling pot, they're full of action and change!