Comments by "George Reynolds" (@karhukivi) on "The World in UV" video.

  1. Glasses don't "see through" things, rather it is light coming in towards us that we receive as "seeing". That is one of the reasons for radio telescopes, they receive wavelengths that pass unaffected through the atmosphere.
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  2. The bees see UV which we can't see, so they probably see a greater colour range than we can even imagine! The video had to use some tricks to demonstrate what we might see if we could see in the UV band.
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  3. They could, but it would have to be silvery and not very attractive. A molecule that absorbs UV and is transparent to visible is hardly noticeable. I wasn't very convinced about sunscreens until I spread a little on a yellow fluorescent pad and shone a shortwave UV lamp on it - the fluorescence was completely gone and the pad appeared black, like the presenter's face! I tried different grades of sunscreen and the best strategy is to buy the highest grade, the lower grades are just more dilute.
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  4. They do wash them but adding "optical white" (a white fluorescent substance) makes them "whiter than white!". Now where did I hear that phrase...?
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