The desktop flamethrower was every chemistry lesson at my school. The fiery demise of many a schoolbook.
Lighting the gas taps wasn't uncommon in mine, either. Or connecting them to the water taps to see who won.
Given the inflammability of the entirely polyester school uniforms, I'm surprised that so many of us survived chemistry.
I remember a boy in my class managed to set fire to his generously-sized school-issue polyester sleeve in the first week of secondary school
SCIENCE lessons, which was then patched by his mum and remained with him until at least year 10. (Perhaps counter-intuitively, this was not a subject of ridicule because setting fire to yourself is much more cool than wearing embarrassing school uniform.)
More legendary was the time someone in not-my-chemistry-set re-enacted the end of
Die Hard 2 using a sink full of some alkane or other.
I don't think I blew up anything at school, unless you count releasing the magic smoke from electronic components.