This is a very easy way to showcase the three different states of matter, nearly too easy. Because of its simplicity, I fear it may lack the level of engagement necessary to keep interest from the young learners performing this activity. The activity could be made even more interesting if the balloons were quickly transfered between hot and cold environments (possibly my using dry ice and warm water) to show more drastic phase changes. It's great that the resource provides discussion questions, but the quality of the lesson could be improved with additional resource to extend the activity.