An elementary treatment of the reverse sprinkler.

Autor/in	Jenkins, A.
Titel	An elementary treatment of the reverse sprinkler.
Quelle	In: American journal of physics, 72 (2004) 10, S. 1276-1282 PDF als Volltext Link als defekt meldenVerfügbarkeit
Sprache	englisch
Dokumenttyp	online; gedruckt; Zeitschriftenaufsatz
ISSN	0002-9505; 1943-2909
DOI	10.1119/1.1761063
Schlagwörter	Kognitiver Konflikt; Alltagsphysik; Drehmoment; Druck (Phys); Mechanik; Physikunterricht; Strömungsmechanik; Bewässerungsanlage
Abstract	We discuss the reverse sprinkler problem: How does a sprinkler turn when submerged and made to suck in water? We propose a solution that requires only a knowledge of mechanics and fluid dynamics at the introductory university level. We argue that as the flow of water starts, the sprinkler briefly experiences a torque that would make it turn toward the incoming water, while as the flow of water ceases it briefly experiences a torque in the opposite direction. No torque is expected when water is flowing steadily into it unless dissipative effects, such as viscosity, are considered. Dissipative effects result in a small torque that would cause the sprinkler arm to accelerate toward the steadily incoming water. Our conclusions are discussed in light of an analysis of forces, conservation of angular momentum, and the experimental results reported by others. We review the conflicting published treatments of this problem, some of which have been incorrect and many of which have introduced complications that obscure the basic physics involved. © 2004 American Association of Physics Teachers.
Erfasst von	Arbeitsgruppe Didaktik der Physik, Universität Osnabrück
Update	2005/2