Is it possible to make water "float" inside an upturned glass without pouring out? With science know-how it is!
- Half-fill the glass with water from the bowl. You may need to guess with trial and error how much works best.
- Place the plastic or card on top of the glass so that it covers the opening completely.
- While holding onto everything, turn the glass upside down.
- Now, vary carefully, let go of the piece of plastic/card - best to do this outside or over the bowl! What happens?
If all goes to plan your piece of plastic or cardboard will stay in place and all the water stays in the glass like magic!
So what's happening?
A few different forces are at work here, most notably gravity pulling the water in the glass down versus water cohesion at the edges of the glass where it meets the plastic/card to make a seal, and air pressure pushing the piece of card up.
What would happen if you:
- Tilt the glass or shake it?
- Didn't use any water?
- Slid the plastic or card slowly away (over the bowl)?
- Used a much larger container like a bucket?