hand holding a Styrofoam cup with two Holes with water coming out over a catch basin

 

two swimming batons

 

Code Number: 1G20.30

Demo Title: Leaky Cup Drop

Condition: Good

Principle: Gravitational Acceleration

Area of Study: Mechanics

Equipment: 

Styrofoam Cup with Two Holes, Water, and Catch Basin.

Procedure:

Cover the two holes in the cup and fill about 3/4 full with water. Take your hands off the hole and when desired drop the cup. When the cup is in freefall no water should come out of the holes.

Warning: the cup will not survive the fall.

The swimming batons are an easier way to do this demo. Hold them under water until they are full and then put your fingers over the top two holes. When you are ready, move your fingers off the top two holes and water will stream out of the bottom two holes until the baton is dropped. The demo is easily repeated with this apparatus.

References:

  • Jeffrey C. LaCombe and Matthew B. Koss, "The Make-It-Yourself Drop-Tower Microgravity Demonstrator", TPT, Vol. 38, # 3, Mar. 2000, p. 143.
  • John A. McClelland, "Simulating Microgravity", TPT, Vol. 38, # 6, Sept. 2000, p. 328.
  • Martin Gardner, "Zero Gravity", TPT, Vol. 36, # 3, Mar. 1998, p. 184.
  • Ernie McFarland,  "Inertial Forces on an Overhead Projector",  TPT, Vol. 28, # 8, p. 542, November 1990.
  • Clyde J. Smith,  "Weightlessness for Large Classes",  TPT, Vol. 27, # 1, p. 40, January 1989.
  • Richard Breslow, "Apparent Weightlessness in Free Fall", TPT, Vol. 12, # 6, Sept. 1974, p. 366.
  • Haym Kruglak, "Efflux from an Orifice",  TPT, Vol. 1, # 4, April 1963, reprinted in TPT, Vol. 9, # 9, December 1971.
  • M-188/S-055, "Water/Masses in Styrofoam Cup",  DICK and RAE Physics Demo Notebook.
  • Haym Kruglak, "Apparatus-Lecture Demonstration and Laboratory", A Potpourri of Physics Teaching Ideas, p. 92.
  • David Kutliroff, "33, Free Fall and General Relativity", 101 Classroom Demonstrations and Experiments For Physics Teachers, p. 76.
  • Martin Gardner, "2, Zero Gravity", Smart Science Tricks, p. 10.
  • #175, "Weightless", Janice VanCleave's 203 Icy, Freezing, Frosty, Cool, and Wild Experiments.
  • Robert Ehrlich,  "12.4 - Weightlessness",  Why Toast Lands Jelly-Side Down, p. 183.
  • "Falling Glass of Water", Physics From the Junk Drawer, 3rd Edition, The Science House, North Carolina State University, p. 18.
  • Bobby Mercer, "Weightless Cup", Junk Drawer Physics, p. 27.
  • Tik L. Liem, "The Cup of Coffee Drop", Invitations to Science Inquiry - Supplement to 1st and 2nd Ed. p. 142.
University of Maryland Physics Department QOTW Question #69
University of Maryland Physics Department QOTW Answer #69
University of Maryland Physics Department QOTW Question #70
University of Maryland Physics Department QOTW Answer #70
1G20.30 - Leaky Cup Drop

1G20.30 - University of Maryland QOTW #69
1G20.30 - University of Maryland QOTW Question #70

1G20.30 - University of Maryland QOTW Answer #70