Demonstrations

Terminal Velocity - Coffee Filters

Code Number :	2C30.65 See also: 1C20.18
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: University of Iowa Disclaimer All Rights Reserved..
Condition :	Good
Principle :	Viscosity
Area of Study :	Heat and Fluids
Equipment :	Coffee filters, computer interface with sonic sensor, Parachute.
Procedure :	The coffee filters will reach a terminal velocity in a very short time. There shape makes them particularly easy to use with the sonic sensor, as they float down with very little side to side motion. The second picture shows the relationship between one coffee filter and four coffee filters and their velocities. If you hold the four coffee filters at approximately twice the height of one coffee filter they will hit the ground at the same time. The parachutes can also be used as an example of terminal velocity. Fold the parachute according to the instructions and throw at the ceiling of the lecture room. The chute will unfold and quickly achieve terminal velocity.

References

Ian Lovatt and Bill Innes, "Resistance Is Not Futile: Air Resistance in an Algebra-Based Course", TPT, Vol. 43, # 8, p. 544, (Nov. 2005).

Paul Gluck. "Air Resistance on Falling Balls and Balloons." TPT, Vol. 41, # 3, p. 178, (March 2003).

Richard A. Young, "Improving the Data Analysis for Falling Coffee Filters," TPT, Vol. 39, # 7, p. 398, (Oct. 2001).

Carl Angell and Trond Ekern, "Measuring Friction on Falling Muffin Cups," TPT, Vol. 37, # 3, p. 181, (March 1999).

Steven Herbert, Terrence Toepker, "Terminal Velocity", TPT, Vol. 37, # 2, Feb. 1999, p. 96.

Terrence Toepker, "An Extension", TPT, Vol. 37, # 3, March 1999, p. 132.

Vasilis Pagonis, David Guerra, Sean Chauduri, Brian Hornbecker, Nathan Smith, "Effects of Air Resistance: Dropping a Series of Nested Coffee Filters." TPT, Vol. 35, # 6, p. 366, (Sept. 1997).

Norman F. Derby, Robert G. Fuller, Phil W. Gronseth, "The Ubiquitous Coffee Filter," TPT, Vol. 35, # 3, p. 168-171, (March 1997).

Neil M. Shea, "Terminal Speed and Atmospheric Density", TPT, Vol. 31, # 3, Mar. 1993, p. 176.

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

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

Alan Mironer, "Understanding Drag", TPT, Vol. 20, # 6, Sept. 1982, p. 400.

James A. Lock, "The Physics of Air Resistance", TPT, Vol. 20, # 3, Mar. 1982, p. 158 - 160.

James A. Lock, "The Author Adds Details", TPT, Vol. 20, # 6, Sept. 1982, p. 400.

M.A.F. Gomes, "Fractal Geometry in Crumpled Paper Balls," AJP, 55, (7), July 1987.

M-136: "Flat $ Bills & Coffee Filters," DICK and RAE Physics Demo Notebook.

Robert Ehrlich, "Terminal Velocity of Falling Coffee Filters," Why Toast Lands Jelly-Side Down, p. 40- 42.

Charles Windsor, "Coffee Filters."

Mail Questions and Comments to: Dale Stille