when a jar of water is flipped upside down and doesn’t spill, it’s because of air pressure, but I don’t understand why it doesn’t spill out.

Question

Here is a link to the experiment. https://www.reddit.com/r/Damnthatsinteresting/comments/174riz3/students\_find\_it\_witchcraft\_when\_the\_teacher/

In: 1

Answer 1

So what’s happening with the jar is that the air is pushing “up” and this holds the water in place. It’s no different than if you were to put your hand up to the jar and hold the water in, really.

The reason this is weird and seems strange is that normally air is pushing in all directions, up, down, left, right, etc. And that means the effect kind of gets canceled out.

But the jar is protecting the water from being pushed down by air, so the only force that’s left is air pushing up on it, and that’s plenty of force to keep the water in place.

Answer 2

How come when you have a jar of air under water, the water pressure doesn’t keep the air in?

Answer 3

It has a metal gauze inside it so the surface tension between the sides of the holes in the gauze and the water is the factor most at play here.