PURPOSE: To demonstrate the effects of resonance in pendula of varying lengths.

DESCRIPTION: Apparatus is a straw (pen/pencil) with light thread of 3 lengths hanging from it. Paperclips (or other objects) are attached to the bottom of the threads and are allowed to swing. Tell your students to concentrate their thoughts on one paperclip, then by using "sleight-of-hand", excite that pendula at its resonant frequency. Ask for explanations why the other paperclips don't move.

SETUP TIME: 10 min to build the apparatus.

COMPONENT LIST:

Straw, thread, paperclips				Most offices or demo room (N021)

SUGGESTIONS: Being a good magician doesn't help for this demonstration. In fact, the more the students see your hands move, the smarter they feel!

REFERENCES: PIRA 3A60.30

OTHER NOTES: