[CTcard]

In mid-1950s he was a TA in a high school chemistry class. 

High schools have TAs?



My version was in my first year of teaching. Intro course for physics majors, and we're talking equations of state and all that, and I decided to demonstrate PV=nRT with helium balloons and liquid nitrogen. That was all well and good, but for kicks I thought that while I had the nitrogen out I'd do a bunch of fun "things are weird when really cold" demos including the classic blow up a soda bottle as liquid turns to gas.

The room only had the mini steel garbage cans, and I somehow decided it would be a good idea to flip the can upside down over the bottle to containt the shrapnel. I put the LN2 in the bottle and placed it under the can at the start of lecture and told the class we'd come back to that later.

As lecture was nearing the end, nothing had happened yet and I was getting a little worried. I couldn't leave it there and I didn't want to pick it up when it might explode. But that didn't turn out to be th problem. Right on schedule, just as I said, "that's it for today", the bottle explodes, the can launches into the air in a remarkably stable fashion, slams into ceiling taking out the ceiling tile with a circular hole, and misses the giant flourescent light by an inch or two.

After a moment of shock, I have a near heart attack at the near miss and the class gives me a standing ovation for the show.
Eventually I confessed it wasn't all exactly as planned.

[CTcard]

In mid-1950s he was a TA in a high school chemistry class. 

High schools have TAs?



My version was in my first year of teaching. Intro course for physics majors, and we're talking equations of state and all that, and I decided to demonstrate PV=nRT with helium balloons and liquid nitrogen. That was all well and good, but for kicks I thought that while I had the nitrogen out I'd do a bunch of fun "things are weird when really cold" demos including the classic blow up a soda bottle as liquid turns to gas.

The room only had the mini steel garbage cans, and I somehow decided it would be a good idea to flip the can upside down over the bottle to containt the shrapnel. I put the LN2 in the bottle and placed it under the can at the start of lecture and told the class we'd come back to that later.

As lecture was nearing the end, nothing had happened yet and I was getting a little worried. I couldn't leave it there and I didn't want to pick it up when it might explode. But that didn't turn out to be th problem. Right on schedule, just as I said, "that's it for today", the bottle explodes, the can launches into the air in a remarkably stable fashion, slams into ceiling taking out the ceiling tile with a circular hole, and misses the giant flourescent light by an inch or two.

After a moment of shock, I have a near heart attack at the near miss and the class gives me a standing ovation for the show.
Eventually I confessed it wasn't all exactly as planned.