Conceptual Physics Lab: Investigating the Visible Spectrum
Problem: How can you use electromagnetic waves within the visible spectrum to identify unknown
gases?
Part 1: Investigating how light is produced
Directions: Open the PhET model, "Neon Lights and other Discharge Lamps". In the options (lower
right on the model), check the spectrometer and squiggle settings. Notice the energy diagram on the right of the
model, as well as the red arrow labeled "Energy at collision".
1. Fire a single electron towards the hydrogen atom. Describe what happens in a step by step
fashion. [N.B. - It may be helpful to utilize the Run in Slow Motion option for this part.]
2.
3.
4.
How can the "Energy at collision" arrow be manipulated in this model?
How is light "produced", according to this model?
What role does energy play in the production of electromagnetic waves (light)?