Yeah I've seen that demonstration in school too. But if the teacher was willing to do it in school, with kids, how dangerous was it really?
Yeah I've seen that demonstration in school too. But if the teacher was willing to do it in school, with kids, how dangerous was it really?
Along with the other commenter, I'll add that a classroom is usually a lot bigger than a home dining room or other domestic party locations. That size also helps things dissipate instead of reflect. Not sure by how much but I'm sure it does something.
My chemistry teacher told us how once when he ignited helium in a test tube, the tube broke and he ended up with pieces of glass embedded in his skin. The students had face masks and he was looking the other way "just in case" for this "safe" experiment but he could have easily been blinded.
Things can always go wrong. We probably shouldn't strive for 100% safety because they we'd spend our lives in a padded cell. But we also shouldn't assume things are safe because they're common or routine.
You can get permanent hearing damage from that demonstration if you stand right next to that balloon.
Makes sense.