## Reflection: Perseverance A Closer Look at Photoelectricity - Section 3: Intro to Photoelectric Effect Simulation

One of the Four Big Ideas of the recent electromagnetic investigation was to see evidence that light behaved like a particle. Despite my best efforts to provide students with photocells and colored light bulbs (red, green, and blue, as well as a black light), we did NOT witness the desired outcome - no matter what color bulb we used, the photocell produced current.

There may be good reasons for this. the bulbs may not have been monochromatic though, to the eye, they looked like predominant color. The photocells may have been especially efficient and sensitive to even the lowest frequency light we produced. The result was that there really was no reason to abandon the wave model to explain the flow of electricity! I needed to come up with another experience to supplement our lab work and chose to use a simulation.

The University of Colorado has a wonderful simulator that I used earlier in the unit to introduce some of the ideas of photoelectricity. Today, I returned to this simulator for an experience that, I hope, provides students with the evidence they need to abandon the wave model of light.

To expedite the process, I have students collect data on a single metal and share the data in a common spreadsheet that can be analyzed at the board. On this first day, I want students to collect data that captures the relationship between frequency and the kinetic energy of the most energetic electrons. In our next setting, we'll spend some time exploring the cut-off frequency and recognizing the limitation of the wave model at that time.

# A Closer Look at Photoelectricity

Unit 4: Electromagnetics
Lesson 15 of 17

## Big Idea: Data from different metals show similarities and differences in the photoelectric effect, highlighting fundamental physics phenomena.

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Standards:
75 minutes

### Timothy Brennan

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