Ignorant? You're going to say someone else is ignorant while comparing some mild gas expansion in a closed bottle to devices designed to maim and kill. It's almost like, why am I even writing this comment...
I am just making this post to point out that what she was doing COULD have been dangerous or fatal, it just wasn't.
Fortunately plastic containers will fail long before the buildup of pressure becomes too powerful. But in general, that kind of explosion does and can kill.
The most she deserves in this case is a rap on the knuckle. I'd say not even that - maybe a gentle talking to - "be inquisitive, explore ... but be a little more careful."
What is ignorant is the fact that reddit/hn is willing to completely ignore the fact that the intent was to mix chemicals and make an explosive device. Ask any school administrator if a student of any race would be punished for that.
Look at it from an administrators perspective, they are legally obligated to maintain a safe environment for children. If another student was injured it would be their job/income/family on the line.
But I'd like to know what chemicals were in the bottle before going too far into a conversation on this, as that defines how dangerous her experiment was. There are certain household chemicals that you do not want to see in a reaction that generates a small explosion and smoke. Some that will burn the lungs severely or cause blindness.