Wine glasses with colored water, wooden dowels on two tables

 

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.
1F20.40 - Stick and Wine Glasses