Beaker of water and a digital scale
finger in the beaker of water

 

Code Number: 2B40.15

Demo Title: Buoyancy - Finger, Water, and Scale

Condition: Excellent

Principle: Buoyancy

Area of Study: Fluids

Equipment: 

Digital Scale, Beaker, and Water.

Procedure:

Place the beaker of water on the scale and tare the scale.  As you press your finger into the water the scale reading will increase.  Basically this reading is a direct measurement of the buoyant force that the water is exerting on the finger.

References:

  • Michael M. Hull, Shizuka Nakayama, Sachiko Tosa, "Poking Your Finger into a Cup of Water on a Scale: Simple Adhesion Force Experiment", TPT, Vol. 61, #2, Feb. 2023, p. 128.
  • Amanda C. Tenhoff, Adam J. Gerenz, and Jeffrey A. Jalkio, "Buoys and Springs – Building Connections Between Math and Physics", TPT, Vol.54, #9, Dec. 2016, p. 556.
  • Alpha E. Wilson, "Buoyant Beaker Balls: Another View", TPT, Vol. 54, #8, Nov. 2016, p. 452.
  • Paul Hewitt, "Hewitt's Response", TPT, Vol. 54, #3, Mar. 2016, p. 132.
  • Carl Mungan, "Buoyant Beaker Balls", TPT, Vol. 54, #3, Mar. 2016, p. 132.
  • Paul Hewitt, "Answer to January 2016 Figuring Physics Question", TPT, Vol. 54, #2, Feb. 2016, p. 124.
  • Pirooz Mohazzabi and Mark C. James, "A Simple Apparatus for Demonstrating Fluid Forces and Newton's Third Law", TPT, Vol. 50, #9, Dec. 2012, p. 537.
  • James J. Carr, "Demonstrating Newton's Third Law", TPT, Vol. 42, #3, Mar. 2004, p. 132.
  • Paul Hewitt, "Figuring Physics: Submerged Teabag", TPT, Vol. 41, #7, Oct. 2003, p. 384.
  • Paul Hewitt, "Figuring Physics: Beaker and Water", TPT, Vol. 39, #4, Apr. 2001, p. 204.
  • Eric Kincanon, "Explanation of a Buoyancy Demonstration", TPT, Vol. 33, #1, Jan. 1995, p. 31.
  • Robert Ehrlich, "6.3, Buoyant Force on your Finger", Why Toast Lands Jelly-Side Down, p. 102.
  • R. W. Pohl, "7. The Upward Thrust of Liquids on Solid Bodies Immersed in Them", Physical Principles of Mechanics and Acoustics, p. 163.
  • Martin Gardner, "Finger in the Bowl", Entertaining Science Experiments with Everyday Objects, p. 83.
  • Borislaw Bilash II and David Maiullo, "Fingering Out Buoyancy", A Demo a Day: A Year of Physics Demonstrations, p. 188.
  • Janice VanCleave, "4, Weigh Your Hand", Teaching the Fun of Physics, p. 13.
University of Maryland Physics Department QOTW Question #10
University of Maryland Physics Department QOTW Answer #10
2B40.15 - University of Maryland QOTW #10