What happens when you blow air between two pieces of paper?
Some of us predicted that, like a balloon, the pieces of paper would jump apart because of the extra air being forced between them. Others predicted that the two pieces of paper would squeeze closer together because the air that we blow travels faster than the air on the other sides of the pieces of paper. The still air exerts more pressure that the moving air and so the pieces of paper get pushed together by the air on the sides of the paper, causing the sheets of paper to be pushed closer together. Who do you think was right? This is very easy to try.
Next we would like to know what happens to a strip of paper if we blow across the top?
Again some of us predicted that the air we blow on the top of the paper will be heavy and will force the strip of paper to point downwards. Others predicted that the piece of paper might rise because the air we blow on the top of the paper will be moving faster than the air underneath the paper. Like last time this might make the piece of paper rise upwards. What do you think? This is Bernoulli's principle and is the reason that aeroplanes can take off and fly in the sky.
Finally we tried a rather cool trick.
Did you know that you can take a paper cup (or empty fizzy drinks bottle) out of a glass just by blowing on its rim? When we blow hard across the rim of the glass the paper cup (or can) just pops out of the glass. Again, this is because the air around the rim of the glass is now moving very quickly while the air under the cup is much stiller, which puseds the paper cup (or can) out of the glass. It was spectacular.