[Ng Jing Kiat]

Ng Jing Kiat asked the Naked Scientists:
   
I am just wondering, how can we create a small rocket figure (which requires very basic parts) and enable it to take off after pumping water or air.

Thank you very much!
What do you think?

[Kryptid]

Isn't this the same method that toy water rockets use? Is the question here about whether such a thing could work for a real rocket? I don't think it would on such a large scale.

[Bored chemist]

This sort of thing?
http://www.bbc.co.uk/bang/handson/waterbottlerockets.shtml
I spent most of a summer playing with these when I was a kid.