What Happens When You Play with a 3 Dollar Diffraction Grating?

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SUMMARY

The discussion centers around the practical use of a $3 diffraction grating to observe the spectrum of light emitted from streetlights. Users shared images showcasing the 0 and 1st order fringes, highlighting the dominance of yellow-red light and the minimal presence of blue light. A light pollution filter was used to effectively eliminate the yellow portion of the spectrum, demonstrating its impact on light perception. The conversation emphasizes the educational value of these experiments in media arts classes, particularly in understanding the electromagnetic spectrum and color perception.

PREREQUISITES
  • Understanding of diffraction gratings and their function in light analysis.
  • Familiarity with the electromagnetic spectrum and atomic transitions.
  • Knowledge of light pollution filters and their application in photography.
  • Basic skills in capturing and analyzing light spectra using a camera.
NEXT STEPS
  • Research the principles of diffraction and how diffraction gratings work.
  • Explore the effects of different light pollution filters on light spectra.
  • Learn about the electromagnetic spectrum and its relevance to color perception.
  • Investigate practical applications of diffraction gratings in media arts and photography.
USEFUL FOR

This discussion is beneficial for educators, media arts students, photographers, and anyone interested in the practical applications of optics and light analysis.

Drakkith
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So I bought a 3 dollar diffraction grating and was playing around with it. Here's a few pictures I took just holding it up in front of my cell phone camera. Notice the bright lines in the spectrum that correspond to specific atomic transitions in the streetlight. The spectrum is dominated by Yellow-Red light and very little Blue, which of course is why the light is yellowish.

The 1st picture is the 0 and 1st order fringes (0 order is just the regular image, no fringes). The 2nd picture is the 1st and 2nd order fringes. The third is identical to the 1st image, but I held up a light pollution filter in front of the grating and camera. Notice the near complete removal of the yellow portion of the spectrum, which should correspond to the light emitted by Sodium in the streetlight. (The light pollution filter is designed to block this specific part of the spectrum to cut down on light pollution when viewing/imaging near or inside of cities)

Also, made a little video with an Oxygen-III filter held in front of it. As I tilted the filter the wavelengths that were passed shifted. Go full screen and high quality to get the best view.
[Apparently I removed the video from my youtube account a few years ago and it has now been lost]
 

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Things like this should be useful in media arts classes (lighting, photography, video, etc).
I took some of these classes and some (but not all) the students did not understand the nature of the electromagnetic spectrum, its relation to light, and our perception of color.
Things like this make matching illuminating light and perceived colors much more real for some.
 
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Weird, it was there when I posted it, but now it is not there.
I put it back, maybe it will stay put this time!
 
BillTre said:
Weird, it was there when I posted it, but now it is not there.
I put it back, maybe it will stay put this time!
Not yours, the one posted by @Drakkith.
 
Wrichik Basu said:
Says video is unavailable...

Hah! I think I removed it from my youtube account! I'll see if I can delete the link.
 
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