My Chemistry teacher did this the first day of class with a coke can, a hotplate, and a basin of water. I have never forgotten the scientific principles behind it, and here’s why.
There were 20-something of us in the classroom, all dying of sleep deprivation since it was the first day back to school, first class of the day. Mr. Moses was that teacher you weren’t sure how to deal with. I mean, the man’s name was Noah Eugene Moses, for starters. He drove a Harley to school, but also drove the bus. He had giant cokebottle glasses and a doofy mustache with shaggy ex-Beatles hair. He always wore suspenders and a grease-stained t-shirt because he had a potbelly and taught the shop/electrical classes. He wasn’t even really lecturing; he was throwing in tidbits of the syllabus in the midst of bad jokes and fun stories. We were all a bit nervous, because none of us had taken a class from him before, but his tests were legendary—nobody had ever made it out with an A (until I did, but that’s another story for another time and involves a really awesome bet and some hair cutting scissors).
Well, as we were fighting to stay awake, and attempting to take notes of whatever he was talking about, he was pacing around the room from here to there, straightening things and moving stuff. He was very scatterbrained, and it was easy to tell from how he kept forgetting where he put his coke. Turns out, that was just a ruse. He had the can filled with just a tiny bit of water, and the things he was moving around were stacks of papers and books hiding the hot plate and water basin. So he set his coke can down onto the hot plate, continued talking loudly enough so we wouldn’t hear the water boiling, and then knocked it over really fast into the water basin.
Three girls fell out of their seats, one dude swore so violently I’m pretty sure the devil himself cringed, everyone at least jumped and screamed, and I actually broke my pen in half.
See, with rapid decompression comes a vacuum, and with a vacuum comes a rushing of air that creates a massive sound. Think “thunder”. That’s the same principle behind it. His little tiny coke can of steam into a bucket of ice water, and we had a bang so loud the band teacher came in from across the hall to see “what was exploding today.” To which Mr. Moses responded, “Nothing, it imploded. Explosions are chapter 3.”
And that’s when I knew it was going to be the best class ever.
