Swinging beam of beads transforming into a simple pendulum of the same length

摘要

Costume jewelry beads are employed to demonstrate how a beam of beads are able to transform into a simple pendulum (single bead) where the pendulum length remains constant throughout.These beads are common and inexpensive for instructors, as well as attractive and exciting for students.Beads are removed from the top, keeping the same pendulum length until a single bead remains.The experimental data deviates about 2%from an ideal theoretical model for the extreme cases of the simple pendulum and rigid rod.Factors leading to the small discrepancies are discussed.This engaging experiment is demonstrated with an accompanying video (Hawes C E and Ruiz M J 2018 Video: Fun with swinging beads http://mjtruiz.com/ped/beads/).