First the serious stuff!
Learn some chemistry and physics while having fun with dry ice!
Dry ice has some unusual properties. We make it from CO2 liquid by turning it into a solid, but as soon as it is made it starts to change into CO2 gas without forming any liquid. A gas forming direct from its solid when it warms up is called sublimation.
We need approx 2.2 kg of liquid to make 1 kg of dry ice and one kg of dry ice sublimes into 509 litres of CO2 gas under normal conditions (zero degrees C and one atmosphere pressure).
This explains why sealing a small piece of dry ice in a balloon will blow it up slowly as the ice sublimes. If you put the ice in a pot with a push on lid the same process will blow off the top, but never put it in a sealed container as that can blow up and cause serious injury.
In the same way that subliming ice will blow up a ballon it will also make bubbles if put in soapy warm water. Big bubbles or lots of small ones can be made, and even frozen ones. Have a look at Atomic Tom’s video and enjoy the show.
If you are thinking of hosting a dry ice show for your pupils, Atomic Science work throughout the Midlands and beyond and would be pleased to hear from you on firstname.lastname@example.org or www.atomicscience.org