Supercritical fluid

Okay, so imagine you have some water, and you heat it up on the stove. As it gets hotter, it goes from a solid (ice) to a liquid (water) to a gas (steam). All of these states of matter have different properties, like how they look and whether they can take up space.

Now, what if you kept heating up that water even more, until it was way, way hotter than boiling temperature? At that point, the water turns into something called a "supercritical fluid." This is a substance that has properties of both a gas and a liquid, all at the same time.

To explain it like you're five: you know how sometimes you're not sure if you want chocolate milk or regular milk, so you mix them together and get something that's like both but also different? A supercritical fluid is kind of like that, but with gas and liquid. It's a special mixture that doesn't exactly look or act like either one on their own.

Scientists like to use supercritical fluids in all kinds of experiments because they have some pretty cool properties. For example, they can dissolve things that are normally hard to mix into liquids or gases, like certain chemicals. They can also be used to clean things like computer chips or delicate medical equipment, because they don't leave behind any residue like regular cleaning agents might.

Overall, supercritical fluids are a pretty neat part of science that you might learn more about as you get older and study things like chemistry and physics!