1G30.30 - Hourglass

Code Number:
Demo Title:
Weight of an Hourglass
Area of Study:
"Hourglass" made of two soda bottles (half filled with water) connected by a tornado tube, scale accurate to 0.1g, timer, video camera and power supply.

Fill the soda bottles as shown and connect them together with the tornado tube apparatus. Set them on a scale and tare. Turn the bottle upside down allowing the water to move from the top bottle to the bottom. Observe the scale reading during this process which should be different from the starting reading.

  • Metin Yersel,  "The Flow of Sand",  TPT, Vol. 38, # 5, p. 290, May 2000.
  • Ian H. Redmount,  "The Weight of Time",  TPT, Vol.  36, # 7, p. 432, Oct. 1998.
  • Little Stinkers, "More on 'Weight'",  TPT, Vol. 2, # 2, Feb. 1964, p. 91. 
  • K. Y. Shen, Bruce L. Scott, "The Hourglass Problem", AJP, Vol. 53, # 8, Aug. 1985, p. 787.
  • Walter P. Reid, "Weight of an Hourglass", AJP, Vol. 35, #4, Apr. 1967, p. 351.
  • Jearl Walker, "2.16, The Weight of Time", The Flying Circus of Physics With Answers", p. 26.
  • Physics Questions # 66 and # 6, Department of Physics, University of Maryland.
  • Jearl Walker, "2.107, Flows in Hourglasses and Silos", The Flying Circus of Physics Ed. 2, p. 128.
  • Robert Ehrlich, "Weighing an Hourglass", Why Toast Lands Jelly-Side Down, p. 38- 40.
  • Neil. A. Downie, "Everlasting Hourglass", Ink Sandwiches, Electric Worms and 37 Other Experiments for Saturday Science, p. 20.
  • Julius Sumner Miller, Q127 & A127, Millergrams II – Some More Enchanting Questions for Enquiring Minds, p. 18 & 81.
  • "The Time Glass", Pike's Illustrated Catalogue of Scientific & Medical Instruments, 1984, p. 140.
  • Queen's Catalogues Vol. I, Catalogue of Ophthalmology, p. 173.

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