path discussions. The one under consideration this time, is directly connected to the plot provided and the STEM idea deals with light’s wave characteristics. (You can always start with light rays as a review and then move on to waves).
The plot shows that the meter responds to the short wavelength light but does not have much (if any) reading in the longer wavelength region of the spectra. The puzzle indicated that the meter is battery powered, is being used in a dark forest, and is supposed to be sensitive to red light. Since Rudolph is in good health, the meter would not be necessary if his nose did not glow at all. (They would see that right away). Thus, the question is not if his nose is “off,” but if his nose is bright enough. (Remember “… ” then one foggy Christmas eve, Santa came to see…”) Since the meter is suggesting that his nose is “off” or almost “off”, there is something wrong with the meter. Of course, the meter could just be busted, but a first corrective action, especially since it is almost time to get that sled on its way, is to change the battery. Thus, the puzzle does not have a slam dunk correct answer, but it does allow you to emphases an early, if not the first, step in electronic equipment trouble shooting! “Check power and Ground!”