A DVD can split the sun light in several colours as a prism. But is it possible to see spectral lines? I observed sometimes thin dark lines like that in the upper part of the disk. But I'm not sure if it is some kind of interference.dvd1 dvd2

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    $\begingroup$ I know that if you take the reflective coating out what you get is basically a circular diffraction grating. If you cut a square out of it you may use the square as a grating in DIY spectrometers $\endgroup$
    – ErickShock
    Commented Feb 12, 2020 at 1:43
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    $\begingroup$ on the line of @ErickShock I found this publiclab.org/system/images/photos/000/026/339/original/… . $\endgroup$
    – anna v
    Commented Feb 12, 2020 at 5:23
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    $\begingroup$ slittlefair.staff.shef.ac.uk/teaching/phy217/lectures/… According to this article the spectrometers resolution is both determined by the number of lines of the diffraction grating and the slit width of the spectrometer. If the light is just coming from the sun with no slit then it is the limiting factor to the resolution. $\endgroup$
    – ChemEng
    Commented Feb 12, 2020 at 5:24
  • $\begingroup$ But there is still good information to get without the slit as can be seen from this video about flame tests youtube.com/watch?v=ycLltqzAEZ8 $\endgroup$
    – ChemEng
    Commented Feb 12, 2020 at 5:33
  • $\begingroup$ See the image in my answer here physics.stackexchange.com/questions/464911/… $\endgroup$
    – user137289
    Commented Feb 12, 2020 at 6:15

1 Answer 1


You can make a spectrometer out of a cereal box and a DVD or CD.

Some construction is necessary because you need to illuminate the DVD at an angle, with a narrow slit, and view the results.

Whether you can see some of the broader absorption lines from the Sun, I'm not sure. You can certainly see emission lines from bright lamps, but that is easier.

Cereal box spectrograph.


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