I have students try and find how many ml are required for a soda to stand on its side. It's one of the many ways I teach about center of mass. I do let the students drink the content which they enjoy. That, and soda isn't allowed in the classroom except on this day.
Surface Tension, Balloon Rockets and More Physics Science Fair Topics
Students take the class outside to describe Forces in Motion. It's always nice getting outside, moving around, and discussing concepts from class. Students must describe the physics associated with one of their special skills or hobbies.