Bell jar

A bell jar is like a big, clear jar or a vase that is shaped like a bell. You can put all sorts of things inside it, like flowers or fruits, but scientists also use a special kind of bell jar to do experiments.

When they put something inside the bell jar, they can take almost all the air out of it, which means there's no air left for the things inside to breathe. That's because air is made up of tiny particles called molecules that are always bouncing around and pushing against things. When there are fewer molecules knocking around inside the jar, there's less air pressure, which makes it harder for things inside to move or stay together.

If you put some water or a feather inside a bell jar and then take the air out, you'll see something cool happen. The feather will float in the air, and the water will boil and turn into gas!

Scientists use a bell jar to study what happens to things when there's no air, or when the air has different amounts of pressure or different gases mixed in. They can use it to test different materials, chemicals, or even living organisms to see how they react to different conditions.

So, a bell jar is a fancy jar that helps scientists see what happens when there's no air around. Pretty neat, huh?