College of Liberal Arts & Sciences
8B10.50 - Sunspots
Lay the light bulb on the overhead projector and focus so that a clear image of the filament is produced. Turn off the overhead projector and turn up the Variac until the filament glows with a yellow to orange color. Leave the Variac at that setting and turn on the overhead projector. Since the light coming out of the overhead projector is produced by a hotter filament the filament image of the bulb will again appear dark or non-glowing (A Sun Spot).
- Thomas K. McCarthy, "A Doorway Can Be A Sunspot, Too!", TPT, Vol. 35, # 6, Sept. 1997, p. 334.
- Thomas O. Callaway, Harry D. Downing, and Glen T. Clayton, "Classroom Demonstration of Sunspots", TPT, Vol. 20, # 3, Mar. 1982, p. 171.
- Jay M. Pasachoff, Daniel B. Seaton, Kevin P. Reardon, "Sunspots and Their Cycle", Physics Today, Vol. 76, #2, Feb. 2023, p. 54.
- Wallace A. Hilton, "G-9", Experiments in Optical Physics, p. 15.
- "March 9, 1611: Dutch Astronomer Johannes Fabricius Observes Sunspots", APSNews, March 2015, Vol. 24, # 3, p. 3.
- "Quiet Interlude in Solar Mass", AD Astra, Fall 2013, p. 55.
- "Astronomy Demonstrations", PIRA News, Vol. 9, No. 3, p. 21, January 1995.
- Carrina Storrs, "Solar Force Field", Popular Science, October 2009, p. 12.
- H.J. Press, "Image of the Sun", Giant Book of Science Experiments, p. 11.
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