Explore sublimation with dry ice.
Dry ice is very cold. You may wish to use gloves or tongs.
Chemicals and Solutions
Place a piece of dry ice in a balloon and tie the balloon. As the dry ice sublimes the balloon inflates. Pass the balloon around the classroom. Or you could place several pieces of dry ice into an Erlenmeyer flask and then attach the balloon over the mouth of the flask. This balloon will inflate as the dry ice sublimes.
Sublimation Temp = -78.5° C