There is a risk that you'll get a face full of water with this experiment but it's a great way to learn all about air pressure and just one of those experiments that's got to be seen to be believed!
What do I need:
- A glass
- A piece of paper or cardboard
- Possibly a plate or bowl to catch the water!
How do I do it?
STEP1 - First things first...fill your glass of water around one third full.
STEP2 - Put a piece of paper or cardboard (cardboard does work slightly better but a good old piece of copy paper will still do the job!) over the top of your glass.
STEP3 - This is the tricky bit! Hold the paper flat across the top of your glass and quickly flip the glass upside down. As long as you flip it over quickly the water won't come out!
STEP4 - Optional: Hold the upside down glass of water over either your head or preferably someone else's head!
What's going on?
This is a great example of air pressure in action! Everyone presumes that the water will just drop straight out of the cup but as the water forms a seal with the glass the water can't fall because of the air pressure 'sucking' it back up! The air pressure of the air in the room also pushes it up too!
More Fun Please - Experiment like a real scientist!
- Does putting a different amount of water into the glass make a difference?
- How about varying whether you use card or paper to cover your glass?