Volcano
 

Instead of the childish NaHCo3 and Vinegar volcano, I heard that you can make a pretty cool volcano using ammonium dichromate by lighting it on fire.

Is this true?

I suppose it is:

http://www.chem.uiuc.edu/clcwebsite/ammvol.html

I've also found in my experimenting with meal powder that you can rig up a makeshift volcano. Just add more than enough KNO3, that way there will be enough molten KNO2 byproduct to simulate molten lava. What's interesting is that the O2 gas produced from KNO3 decomposing causes the molten KNO2 to bubble, hiss, and skeet across whatever surface you have it on. Pretty neat stuff.