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ERIC Number: EJ1083307
Record Type: Journal
Publication Date: 2006-Dec
Pages: 2
Abstractor: As Provided
ISSN: ISSN-0031-921X
A Delicate Balance: Hovering Balloons in an Air Stream
Gluck, Paul
Physics Teacher, v44 n9 p574-575 Dec 2006
Science museums and popular physics shows often exhibit a blower in whose air stream a ball is held hovering in equilibrium some distance above the jet's orifice. The weight of the ball, "mg," is balanced by the drag force of the turbulent air stream, often written as ?Cv[superscript 2]A, where "?" and "v" are the density and velocity of the air, "A" is the effective area of the ball, and "C" some drag coefficient depending, among other things, on the surface roughness. This paper describes a ball and balloons of various sizes supported stably stacked one above the other in a vertical air stream from a blower.
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A