Science teacher showed students the reaction between sodium metal and water. The teacher did the experiment carefully, only slicing off a small piece of sodium and adding it carefully to a earlenmeyer flask.

Unfortunately, some of the students thought it was cool and wondered what would happen if they scaled up the experiment. One pound of sodium metal was taken from the science teacher and thrown in the toilet. The explosion shut down the school for a couple of days.

Actually, it could have been much worse. The sodium reacted with all the water in the toilet. The students were reaching to flush when the explosion hit. If they had flushed, the explosion would have been much worse.

Another friend ended up with boiling acid landing in their mouth when overheated an experiment – so another lesson is ‘keep your mouth shut in the lab’

Takes me back to the good old days (they really weren’t that good!) watching a premed student put a beaker of benzene on a Bunsen burner to heat. The elapsed time between the sighting and the fire was too short to intervene. And there’s the vision of the grad student who endeavored to return an unused, rather large, chunk of sodium to the jar from which it came. Unfortunately, the jar was on his desk about 20 feet from the hood where he had used the sodium, and there was a very wet sink in between. His attempt to carry the chunk to the jar balanced on a narrow, flat spatula was, alas, unsuccessful. Fortunately (in terms of the glorious ensuing pyrotechnics, that is) it was caught by the sink. Also, even more fortunately, no one was hurt, but that was one fast lab evacuation! I needn’t go into the consequences of overpipetting fuming nitric acid by mouth.

In retrospect, there is some humor in these incidents but I’m glad lab safety is taken more seriously now.