Another fun demonstration to add to a science unit, use for a science night, or show students just for fun. No prep time or materials? Use the videos at the end of this post to prompt a conversation about science! Depending on the age of your students this could be demonstrated by a small team of capable students. All you need is two balloons of the same size, about a meter of string, and a drinking straw. The materials are so common students will be able to repeat the activity at home.  🙂     Inflate two balloons to the same size. Tie …