My chemistry teacher in HS told of once coming into the lab and finding two boys stirring 'something'.

"What's this?", he asked.

"Oh, we just..um...mixed a few things...we umm..."

So he looked at the labels of the various ingredients...and how much they had used.... and said, "Don't move! And don't follow me!"

He took the bottle, put a loose stopper in it and went out toward the edge of school grounds and threw it as far as he could....Boom!

Yep...they had managed to cook up some nitro.....