Change in energy as light passes through air/water

[sophiecentaur]

With a cardboard box, an AOL cd, and a dollar store camera.

You deserve a medal for ingenuity and entertainment! Very pretty and it needs some 'analysing, I think.
I know people use CDs as gratings but I think there must be something wrong here. Assuming you have the same amount of throw on your system, the spacings of the spectral components should be the same but there is Yellow on the LED white which has gone for the strip. Perhaps you are not starting with a narrow vertical slot. That could account for much of what I am not happy with - the Cyan band near the top. You shouldn't ever see Cyan without green and blue. There must be an overlap giving a mix of blue and green over a broad band. Have another go with the system, making sure you have a narrow slot and collimated light.
Yes I agree that the Magnitude scale is the wrong way up. They got it wrong - same as the sign of the charge on an electron haha. But we can cope!

 

[OmCheeto]

...Have another go with the system, making sure you have a narrow slot and collimated light.
...

Umm... no. This is not my problem. But you did trigger an idea, which precludes tkyoung from having to wait 2 weeks for diffraction grating, as I now perceive this as more a qualitative, rather than quantitative problem. tk just needs to know if there is "green" in the source light.

Low and behold:

an old CD will do the trick.