50. Swing a Bucket or Tray

Put a liter or two of water into the bucket. Slosh a little out on the floor to show there is water in the bucket. Then swing it in a circle around your head.

"I like to have the students 'participate' in the demonstrations, so I'll walk up into the middle of the audience to swing the bucket around. See, it's not hard! No problem at all keeping the water in! Now let see how slow I can swing it and still keep the water in!"

Swing a tray with wine glass

For a more dramatic demonstration of uniform circular motion, fill wine glass half full of water and place it on a tray with three nylon ropes connected to it. Then swing the tray around. Stopping is a bit tricky so make sure to practice beforehand. This demo really holds the students' attention and excites them - especially if the glass breaks!