This one works with pretty much any sweet that contains sugar, which is awesome. We'd buy dolly mixture, bring it into class, and mess with this during science lessons.
Much less toxic variant is doable with alka seltzer tablets forming a long black worm (sadly i forgot the exact reaction and iam too lazy to look it up- but it is upgradable by using a fat beaker )
Same thing is a experiaent of "Elephant toothpaste" get some dishwashing soap, KI and H2O2 for the foamiest foam lance rising to the skies.
Oooor to get a vid in, too- i present you the iodine clock
nah seriously guys , this stuff is awesome
I never got further than throwing a bottle of shampoo in the local swimming pool's jacuzzi
(and getting kicked out as a result)
If u take a 2L plastic bottle, put pieces of aluminum foil, then put some sumporic acid. Close the bottle shake it a bit and enjoy the result. Oh and you may want to take cover...