For Eighth grade science class I built a Plaster over screen wire volcano. Inside was a five pound coffee can with a saltpeter/sulfur/sugar mix.
I set it off in the grass between the science wing and the cafeteria. It was close to the office so the principal, VP, and secretaries came out to watch.
It put out a Lot of smoke( some sulfur dioxide smoke). The wind blew it first to gas all the office workers. Then gassed us some. And then the wind blew it into all of the open cafeteria windows and gassed a whole lunch period.
I got an A.
By high school, I had moved up to contact explosives and really had the school hopping.
My senior year, I was a lab assistant for a Chemistry class. I had plenty of opportunity for mischief, such as discovering what happens when you add Hydrochloric acid to pure Calcium.
A plume of white vapor was created by it. The teacher thought it was pretty funny.
In 11th or 12th grade, I did a demonstration speech about how to cut laminated glass. I had a piece of sharp glass, a glasscutter, a razor blade, a bottle of denatured alcohol and a lighter. All of which are banned items now.
To cut laminated glass, which has a thin sheet of plastic between two pieces of glass, you score both sides of he glass, spritz it with alcohol, light it and let the flame melt the plastic, which is then cut with the razor blade.
All went well until I poured way too much alcohol on the glass and lit it. I got about a four foot flame. OK, I knew what I was doing and it was fun. Still got a good grade.