Pressure

Pressure is like a big, invisible push on things. Have you ever tried to push a heavy object like a couch, and it was really hard? That's because there was a lot of pressure on it from the weight of the couch.

Pressure can also come in the form of air pushing on things. This is called atmospheric pressure. You might feel it when you go underwater and your ears start to hurt. This is because the pressure from the water around you is pushing on your ears.

Another example of pressure is when you blow up a balloon. You're giving the balloon air, and the air you are putting in is creating pressure inside the balloon. The more air you put in, the more pressure there is, and when there is too much pressure, the balloon pops!

So basically, pressure is like a big, invisible push on things that can be caused by weight or air, and can sometimes cause things to change or even break.