[chris16]

I have a problem concerning a high school assessment. I need to know the best experiment that will knock my teachers socks off literally. The experiment that I need to conduct has to be safe enough to be shown and conducted in a magic show for primary students. If there is someone that can help me with my experiment I would really appreciate this. Thank you 

[Alberto_Kravina]

You could perform experiments like mixing various indicators (phenolphtaleine, methyl orange, methylene blue and so on) with acids and/or bases. Another very common experiment in chemistry shows is the Blue bottle experiment
I don't know if these experiments will "knock off" your teachers

Try to search older threads, maybe you'll find something else in their.

Edit: corrected URL.

[constant thinker]

Alberto_Kravina gave you a good tip.

The Citizen Chemist board on this website has quite a few reactions/experiments. I'm not sure if you'll find exactly what your looking for, but try searching either that board specifically or just the entire site.

The different indicator things can be cool.

Here is a list of some different pH indicators.
http://en.wikipedia.org/wiki/PH_indicator