College of Liberal Arts & Sciences
6A02.15 - Straight Line Propagation of Light
Hold the ball or globe between the point source and the screen. Observe how the shadow size changes as you move the ball closer or farther away from the screen.
- Maja Poklinek Cancula, Mojca Cepic, "A Spreading Shadow In Color", TPT, Vol. 55, #9, Dec. 2017, p. 586.
- Chris Goedde, "Leaping Shadow", TPT, Vol. 49, # 5, May 2011, p. 318.
- Janice VanCleave, "92, How Light Travels", Teaching the Fun of Physics, p. 139.
- Janice VanCleave, "93, What Makes Shadows?", Teaching the Fun of Physics, p. 140.
- Sara Stein, "Where Shadows Fall", The Science Book, p. 199.
Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist. The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose. The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources. Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks. These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage. Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.