One of my dumbest teachers in 7th grade was my math teacher and he had a bad temper that often caused physical outbursts that could easily be triggered some days( punching the black board, throwing books and erasers on the floor or against the wall).
(he was not very emotionaly stable)
One day we were working on basic algebra and came to a series of electrical examples in the text book relating to electricity. They were completely usless formulas that had no real relation to reality. One was, if a 120 volt toaster had an ohmic resistance of ten ohms how many amps and watts does it take. Well the formula said it used 34 amps and around 2700 watts.
We were covering electricity in science class a the same time too so we knew that the math book was wrong!
Several of us more outspoken students challenged this and it triggered a physical outburst. First he slapped the chalk board and said the book is right just look at the equation. Someone else said that is not the right formula for electricity plus algebraicaly it did not add up eather! Then he threw his notes aginst the wall but did not say anything.
About ten minutes later we were doing a physics related question related to a force interaction algebra equation and one of my friends said, Is this one real or totaly made up too?
That teacher angerly growled, its this real! Then blew up and kicked the guy over in his desk!
He broke his own toe (maybe several) and was gone for the rest of the week and came back in a cast and on crutches for several weeks after that!
If he would have done the physics equation he would have realized that the force required to kick a 120 pound kid in a 50 pound metal desk over backwards is large enough to break bones! (he did prove that part right!)
His teaching contract was not renewed the next year.
Years later I worked as a copier repair tech and met up with him at a different school. I mentioned the insident and purposly tried to get a physical outburst or better yet get him to hit me. Lots of students were around too. I wanted to provoke a physical assult and then beat him down in front of the students. Then get him fired and push a minor lawsuite againt the school just to make sure he never got a teaching job again. I did get a good book toss and a slammed door!
(I am not a mean person by nature, I just felt this would have been a good way to prevent him from ever working around childeren. Okay maybe a little spiteful payback was in the motivation too!)
I really did not ever like him and always felt he was not of a suitable disposition to be working around children.
About a year later an unnamed teacher at that school was in the paper for assulting a kid and was fired and has his teaching credentials permanently revoked in order to prevent a lawsuite from being filed agianst the school.
I bet it was him!