LECTURE DEMONSTRATION MANUAL | Instructional Research Lab : ucla physics main page Weightlessness table of contents search
 M.9.10 Weightlessness Two simple demonstration of weighlessness with minimal equipment are described below. (The Local Inertial Frame, M.9.7, is also a demonstration of weightlessness and the fact that Newton's First Law is obeyed in a freely falling frame.) Clip two clothespins on the sides of a rubber band. Hold one clothespin and let the other hang down by the rubber band. The weighing of the second clothespin is represented by the stretching of the rubber band. Now release the upper clothespin. The rubber band goes slack, and the two clothespins and the rubber band fall together. The clothespin(s) are weightless when falling. Suggested by Mr. Wizard. 1. Punch a small hole in the side of a styrofoam cup or a 2 liter bottle near its bottom. 2. Hold your thumb over the hole as you fill the cup with water. Ask the students what will happen if you remove your thumb. 3. Remove your thumb and let the water stream out into a catch basin (a pail) on the floor. 4. Again seal the hole with your thumb and refill the cup. Ask the students if the water will stream out if you drop the cup as you remove your thumb. 5. Holding the cup as high as possible, drop the filled cup into the catch basin. The water does not stream out; the cup and water are weightless. Suggested by Dale Bremmer.