Its not that you legally can't, but if something goes wrong, it is teacher's fault, because they weren't supervising. It is basically to make sure that you are less likely to do something stupid, and hurt yourself and or others.
It is important to listen to your teacher in a science lab because there is some very dangerous stuff in there which could harm you, so if you listen to your teacher, she/he can tell you what to do but safely!
for safety and health
A science lab
Always.
Because some chemicals can explode if their mixed.
The science teacher gave a demonstration of the upcomeing lab.
in my opinion you should tell the teacher immediately
You don't mess with the gas without the teacher's permission. You don't mix chemicals without goggles or without the teacher's permission. You don't horseplay around in the lab.
make a stink bomb in the science lab, then she'll leave
The word Lab in the terms of science (not the dog) is Laboratory.
What the teacher tells you to do. In order to be safe, you need to follow directions carefully and pay attention to what you're doing.
Please tell your teacher and also report it at the main office and see the nurse.