Question: How do you surprise people?

Philip Ratcliffe answered on 14 Nov 2014:

I creep up behind them and go “BOO!” … or, on the other hand, I just dazzle them with science. ;^)
Well, there are lots of surprising things you can do when you know some physics, chemistry or whatever.
Did you ever play with a gyroscope (you know, a little wheel that spins like a top and can balance weirdly say on a string)? Now, if you can find a really big one and set is spinning, when you try to move it or turn it around it fights you in a very strange and unexpected way.
If you can make a little fountain of water, say with a little tube attached to a tap, then put a ping-pong ball on top – it won’t fall off, it sort of gets stuck there.
There’s tons more things but without pictures or a real demonstration, it’s hard to describe them.