Photoelectric Effect: Product Demo
We highly recommend this 5-minute YouTube video featuring veteran educator James Lincoln as he demonstrates the use of a UVC light source to discharge an electroscope. To prep the demo, you can use a piece of zinc (sand the outer layer first!) The video explains what is happening: shorter wavelengths of light are more energetic than longer wavelengths -- they have sufficient energy to "liberate" electrons. To take it further, the author uses a fly stick to put a positive charge on the electroscope. What happens when he tries to discharge it with the UVC light? Nothing, of course. The electroscope must have a net negative charge for the photoelectric effect to happen.
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U.C. Berkeley: Photoelectric Effect-Tennis Ball
If your students are having trouble understanding how and why electrons are ejected in the Photoelectric Effect, they won't after viewing this 6-minute video featuring Berkeley professor Mark Kubinec. In his entertaining, upbeat style, Dr. Kubinec uses analogies to explore how each metal has a specific "energy barrier", which must be overcome to release an electron. The Photoelectric Effect only occurs when light of a high enough energy level is beamed at the metal. We recommend this video after students have completed the hands-on lab in the "Lesson" tab.
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Rimstar.org: Photoelectric Effect and How It Works
This 3-minute video could be a great choice for students who are struggling with the concepts that underlie the photoelectric effect.  The narrator uses a homemade electroscope with a fluorescent ultraviolet light to explain how and why electrons can be made to "release" from a metal. The animation of electrons "escaping" from the zinc metal plate is especially useful for promoting conceptual understanding.
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Physics Girl: The Ultraviolet Catastrophe
In this 6-minute video, Physics Girl Diana Cowern explains how Max Planck used mathematics to solve the "ultraviolet catastrophe" -- a 19th-century prediction that a blackbody would radiate infinite amounts of ultraviolet light. The Ultraviolet Catastrophe was a failure of classical physics to predict observed phenomena. In her engaging style, Diana Cowern explores Planck's epic prediction that light comes in packets or "quanta" and explains how the theory of quantum mechanics sprang from Planck's Constant and, eventually, the genius of Albert Einstein.
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