Just found this news article on a physics demo for an AP physics class that didn't go as planned.
It apparently shows a physics teacher teaching a class a lesson by taking aim at a concrete block.
But he doesn’t quite hit the block correctly and ends up hitting a fellow teacher in a very sensitive area.
Now I'm all for doing demos in class, since not only can they be educational and fun, it also keeps the students from falling asleep. But I don't know if this is a bit on the more "daring" side. There's certainly plenty of chances for things to go wrong with demo such as this.
If anyone has any follow-up news on this, please let me know. The YouTube video implied that the teacher doing the demo lost his job, and there's confusion on the person holding up the blocks and got hit was another student or another teacher.