Day 105: Thin Film Interference Activity

Today’s activity was to determine the thickness of a sheet of paper by placing it between the ends of two glass slides and observing the interference pattern on the glass slides. Based on my experience trying this activity ahead of time, I was concerned it would be challenging to make the observations, and it was. Some groups had more success than others. We ran out of time before any group finished the calculations. We’ll do that tomorrow.


I need to make several improvements for next year. I suspect that a sodium lamp would work better than a variety of CFL bulbs in different colors, which we used. I also found that the binder clip that I used to clamp the two slides together do so too tightly and distorted the slides resulting in curved interference lines rather than a series of parallel lines. I tried using a rubber band instead, but it didn’t hold the slides tightly enough. Maybe I need thicker glass slides.

Anyone else do a lab like this? What equipment do you use? Any suggestions? Thanks!

  ##optics ##practicumlab  

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