Demonstrations

Free-fall and Air Resistance

Code Number :	1C20.18? See also: 2C30.65
Disclaimer:	Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: U of Iowa Disclaimer All Rights Reserved.
Condition :	Good
Principle :	The Effect of Air Resistance on Falling Objects
Area of Study :	Mechanics
Equipment :	5X8 note cards with quarters attached.
Procedure :	Hold the note cards horizontally at some height. When you release them the card with the quarter in the middle should float down in a horizontal position, but the card with the quarter toward the edge will turn vertically and fall at a faster rate. Hold a book in one hand and a piece of paper or note card in the other. Drop them at the same time and observe that the book hits the floor first while the paper only floats down. Repeat the demonstration, only this time place the paper on top of the book. Observe that they travel together at the same rate. You can also use the parachutes to show how a terminal velocity can be achieved using air resistance.

References

"Figuring Physics", TPT, Vol. 44, # 6, p. 390, Sept. 2006.

Jan Benacka and Igor Stubna, "Accuracy in Computing Acceleration of Free Fall in the Air", TPT, Vol. 43, # 7, p. 432, Oct. 2005.

Vasilis Pagonis and David Guerra, Sean Chaudurii, Brian Hornbecker, and Nathan Smith, "Effects of Air Resistance", TPT, Vol. 35, # 6, Sept. 1997, p. 364.

Christopher Brueningsen, Jason Marinelli, Peter Pappano, Kenneth Wallace, "Modeling Air Drag", TPT, Vol. 34, # 7, Oct. 1994, p. 439.

Martin Gardner, Physics Trick of the Month, "A Snap and a Drop," TPT, Vol. 32, # 9, p. 537, Dec. 1994.

Robert Weinstock, "The Heavier They Are, The Faster They Fall - An Elementary Rigorous Proof", TPT, Vol. 31, # 1, Jan. 1993, p. 56.

A. H. Bachman, "Consequences of Mass and Air Resistance for Falling Bodies", TPT, Vol. 31, # 6, Sept. 1993, p. 326.

Robert Weinstock, "But Not Too Fast, Please", TPT, Vol. 31, # 6, Sept. 1993, p. 326.

Richard S. Halada, "Parachutes in the Classroom," TPT, Vol. 31, # 1, p. 50, (Jan. 1993).

"Figuring Physics", TPT, Vol. 29, # 8, Nov. 1991, p. 514.

"Figuring Physics", TPT, Vol. 29, # 1, Jan. 1991, p. 49.

Lewis Epsttein, "Wind Force and Wind Speed", TPT, Vol. 29, # 4, Apr. 1991, p. 196

Frank L. Weichman and Bruno Larochelle, "Air Resistance", TPT, Vol. 25, # 8, Nov. 1987, p. 505.

Margaret Stautberg Greenwood, Charles Hanna, Rev. John Milton, "Air Resistance Acting on a Sphere: Numerical Analysis, Strobe Photographs, and Videotapes", TPT, Vol. 24, # 3, Mar. 1986, p. 153.

John Bozovsky and Ann Brandon, "The Fall of The Ball", TPT, Vol. 21, # 9, Dec. 1983, p. 611.

Paul Latimer, "Do the Leaning Tower Experiment With One Hand!", TPT, Vol. 17, # 5, May 1979, p. 314.

D. F. Jones, "Stabilization Parachutes: A Rigid Body Treatment", AJP, Vol. 55, # 6, June 1987, p. 538.

Gerald Feinberg, "Fall of Bodies Near the Earth", AJP, 33, # 6, June 1965, p. 501.

Robert Ehrlich, "Air Resistance as a Form of Friction," Turning the World Inside Out, p. 44- 46.

Janice VanCleave, "30, Same Speed," Physics for Every Kid, 101 Easy Experiment in Motion, Heat, Light, Machines, and Sound, p. 72.

Mail Questions and Comments to: Dale Stille