[abcdef123]

Hello,

I'm not sure if I'm allowed to ask for advice about this here, and I'm really sorry if I'm not following the guidelines of this site. However, technically, I'm not asking how to create something explosive, nor do I intend to use anything you (hopefully) tell me here in real life. (I don't have any way of getting these chemicals anyway.)

Okay, so now on to my problem:

I am planning on writing a story and I kind of need an explosion to happen in a high school's chemistry lab for the plot to move on. That's why I wondered if anyone could imagine a situation in which some chemical that you could find in a high school detonates. The explosion should be able to trigger a fire alarm (since I need the school to be evacuated). Perhaps an object that contains an explosive substance could be pushed over by a snowball that comes flying in through the window? I'm really not sure how I'm going to set it up yet, so any scenario you can come up with, no matter how unlikely or ridiculous it is, would be very helpful.

You should be aware that my chemistry knowledge is basically nonexistent, so even Google can't help me with this problem. Also, it doesn't have to be 100% realistic, I just don't want to write complete nonsense.

I am sorry if this is not appropriate for this site; I know this is a quite unusual question. Hence, I'd be even more thankful if anyone could help me out.

Thanks in advance!

[ATMyller]

High school chemistry classes do not usually involve chemicals that explode.

Maybe a class that demonstrates reactivity of sodium metal by submerging it to ethanol (which is the common alcohol). Snowball tips the demonstration beaker over in to a sink full of water. That would be able to cause an explosion and setting the alcohol on fire.

[Borek]

Why not just a gas explosion? Triggered by an electrical spark?

Besides, if all you need is to trigger the fire alarm, why do you need an explosion? Won't just a reaction producing fire/smoke work? Basically anything that would produce smoke/fire could work, so it can happen in the chemistry lab, but doesn't have to be related to chemistry. It can add an interesting twist to the plot, as everyone thinks it was chemistry to blame, while it was just something that could happen everywhere.

[abcdef123]

Thank you two so much! These ideas are incredibly helpful, I really appreciate it!