PURPOSE: To show Newton's Third law.
DESCRIPTION: A frame supports a mass on a spring. The spring is stretched and held in tension by a string. This frame arrangement sits atop a double beam pan balance. Burn the string with a match and release the tension in the spring. Observe the reaction of the balance to the movement of the mass. Note that the initial movement is very quick. An instant replay of the action can be made with a video camera and monitor to show frame by frame replay of the reaction.
EQUIPMENT: Frame, mass, spring are storedin mechanics. Double pan balance is stored in general use. Matches are stored in general use. Optional video camera, VCR and monitor.
SETUP NOTES: Use the editing VCR, not the regular VCR.