OTOH, I love it when the lab gets stuff packed in dry ice. When our kids were younger we home schooled them and I used to do all sorts of demos with them using dry ice. Some of my favorites:
Put a piece in a balloon and tie it off then let the balloon ‘self-inflate’ (I actually have used this while at the ER to keep a kid distracted while we sutured him. “OK, I gonna let you help me blow up this glove while we are working… just blow towards it every now and then and it will get bigger as we work on you…”
Stick a small piece in a straw taped to a paper boat and let it propel the boat in a tub of water.
Put a lit candle in an open jar. Drop in a piece of dry ice and watch it snuff out the candle. (Two lessons: gas displacement and the fire triad)
Put a small piece in a bail top bottle with some juice or water and make carbonated liquid.
and of course,
the ubiquitous put-a-piece-in-some-liquid-and-make-‘smoke’
(I once dropped a piece in the mop bucket of a member of our housekeeping staff at the hospital then “accused” her of trying to kill us all by mixing chemicals in the bucket. she couldn’t deny it fast enough…!
I’ve also dropped a piece in the toilet as I left before someone else was going in there…)
Did I mention that dry ice is fun?