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

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Discussion Overview

The discussion revolves around the use of a low-cost diffraction grating to explore the electromagnetic spectrum, particularly in relation to streetlight emissions. Participants share observations and experiences with the grating, including visual results and potential applications in educational contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Meta-discussion

Main Points Raised

  • One participant describes their experience using a diffraction grating to observe the spectrum of streetlight emissions, noting the dominance of yellow-red light and the absence of blue light.
  • The participant shares images showing different orders of fringes and discusses the effect of a light pollution filter on the observed spectrum.
  • Another participant suggests that such experiments could be beneficial in media arts classes to enhance understanding of the electromagnetic spectrum and color perception.
  • Several participants mention issues with accessing a video linked in the discussion, which appears to have been removed or is unavailable.

Areas of Agreement / Disagreement

Participants express interest in the topic and its applications, but there is no consensus on the accessibility of the video or its content, as multiple comments indicate it is unavailable.

Contextual Notes

The discussion includes references to specific visual observations and educational applications, but lacks detailed technical explanations of the underlying physics of diffraction and light emission.

Who May Find This Useful

Individuals interested in optics, photography, media arts education, and those exploring practical applications of diffraction gratings in understanding light and color.

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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