Code Number: 1F20.40
Demo Title: Stick and Wine Glasses
Condition: Good
Principle: Inertia of Mass
Area of Study: Mechanics
Equipment:
Wine glasses with colored water, 1/2" to 1" wooden dowels, window sashing, 24" aluminum rod, pins.
Procedure:
Put a pin in each end of the sashing or the dowel and rest a pin on each wine glass. The object is to break the dowel with the aluminum rod without disturbing the wine glasses.
NOTE: Since there will be flying pieces of wood, protective clothing and eyewear is a must.
Another version of this experiment replaces the wine glasses with eggs in egg cups. Practice or you may end up with " egg on your face"!
Another version is to replace the wine glasses with loops of paper with a 4 inch diameter and a couple of knives that can be clamped to a table. Clamp the knives edge up. Then place the loops over the blades and place the dowel in the loops. The loops will remain intact when the dowel is broken.
References:
- Ernie McFarland, Tom Kehn, "The Fantastic Physics Fun Show", TPT, Vol. 34, # 8, Nov. 1996, p. 512.
- Ernie McFarland, Tom Kehn, "Breaking Broomstick", TPT, Vol. 34, # 8, p. 514, Nov. 1996.
- Karl C. Mamola, Joseph T. Pollock, "The Breaking Broomstick Demonstration", TPT, Vol. 32, # 4, p. 230, April 1993.
- Guy Vandegrift, "Transverse Bending Waves and the Breaking Broomstick Demonstration", AJP, Vol. 65, # 6, June 1997, p. 505.
- Ling Tsai, "The Relation Between Gravitational Mass, Inertial Mass, and Velocity", AJP, 340, April 1986.
- M- 250: "Break String with Large Mass", DICK and RAE Physics Demo Notebook.
- M- 258: "Hanging Mass and Stick", DICK and RAE Physics Demo Notebook.
- Bob Friedhoffer, "Tap-L discussions", 2/4/05.