Photoelectric Effect WebQuest

1. Photoelectric Effect WebQuest • Created by Dan Kurzen for SUNY Oswego EDU 505 with Dr. Yang

2. Introduction • The photoelectric effect refers to the emission of electrons from a metal due to incident electromagnetic radiation of sufficient frequency. • A theoretical explanation of the phenomenon by Albert Einstein led to his Nobel Prize in physics in 1921. • Today, the photoelectric effect is utilized in many technological devices that use photocells like streetlights, solar panels, garage door electric “eyes,” and night-vision goggles.

3. Task • You will learn about the photoelectric effect so that you can explain what the effect is and how it works to someone else. • You will learn about the history behind the discovery and explanation of the photoelectric effect by researching the role different scientists played. • You will learn about how the photoelectric effect is used in several prominent technologies.

4. Process/Resources • What is the photoelectric effect and how do we explain it? • Visit http://www.youtube.com/watch?v=kcSYV8bJox8 to see how different colors of light (i.e. different energy photons) affect the emission of photoelectrons. • Visit http://hyperphysics.phy-astr.gsu.edu/hbase/mod1.html#c1 to read the theory behind the photoelectric effect. • Visit http://phet.colorado.edu/en/simulation/photoelectric and select “RUN” to explore how the frequency and intensity of light, as well as substrate material affect the emission of photoelectrons. • Visit http://www.youtube.com/watch?v=GpcWc5KLVRo to learn how the photoelectric effect can’t be explained by the wave theory of light.

5. Process/Resources • Who were the major “players” in the discovery and explanation of the photoelectric effect and what role did they “play?” • Visit http://galileo.phys.virginia.edu/classes/252/photoelectric_effect.html to read about the development of the discovery and explanation of the photoelectric effect. • Visit http://www.aip.org/history/einstein/essay-photoelectric.htm to read about how Einstein extended Planck’s work to explain the photoelectric effect. • Visit http://physweb.bgu.ac.il/COURSES/LAB_B/Photo-Electric/fulltext.pdf to read an overview of the history behind the photoelectric effect.

6. Process/Resources • What are some common technological devices that use the photoelectric effect and how do they use it? • Visit http://www.wisegeek.com/what-is-a-photomultiplier-tube.htm to learn how a photomultiplier tube amplifies a signal generated by the photoelectric effect. • Visit http://www.physics.org/article-questions.asp?id=51 to learn about how solar cells manipulate photoelectrons to generate electricity from light. • Visit http://electronics.howstuffworks.com/gadgets/high-tech-gadgets/nightvision.htm to learn about how night-vision works.

7. Evaluation • Create a multi-media presentation (PowerPoint, Prezi, Glogster, etc.) in which you do each of the following: • Explain the photoelectric effect. Be sure to address threshold frequency, work function, and photoelectrons in your response. • Summarize the history of the discovery and explanation of the photoelectric effect. Be sure to include Planck, Thomson, Hertz, Lenard, Einstein, and Millikan in your response. • Identify one technological device that utilizes a photocell and the photoelectric effect to accomplish a useful task and explain how the device works.

8. Evaluation

9. Conclusion • You should now be able to explain the photoelectric effect, the history behind its discovery, and give an example of a technological device that utilizes the effect in order to operate. • Perhaps now you may research one of the following to expand your learning: • Other “famous” effects • More about Planck, Thomson, Hertz, Lenard, Einstein, and/or Millikan • Additional aspects of quantum mechanics which has grown tremendously since the “quantum revolution” and the discovery of the photoelectric effect

10. Teacher Page WebQuest created by: Dan Kurzen - graduate student of SUNY Oswego (Spring 2014) and physics teacher at Skaneateles HS, Skaneateles, NY Intended audience: Students enrolled in a physics class or anyone interested in learning about the photoelectric effect