|Do rainbows also have ultraviolet bands and infra
red bands and we just dont see them?
|Question Date: 2004-10-22|
Yes, they must. However, the reason why they are
called ultraviolet and infrared is precisely
that the human eye does not see them.
Theoretically, yes, but there is one problem
with that, that being that water is opaque to
both the ultraviolet and the infrared. Near
infrared and near ultraviolet (very close to being
visible) probably do have bands just as you
describe them, but farther afield the light gets
Rainbows do have UV and IR bands.
Rainbows are the result of water droplets acting
as a prism to separate light (electromagnetic
radiation). The only difference between UV and IR
light versus visible light is the wavelength (and
also the frequency). People can't see these bands
because our eyes are not sensitive to the UV or
IR. However, it's probably worth nothing that
these bands might suffer from other effects in
a rainbow. For example, IR light may be
absorbed by atmospheric molecules, and the UV
light may be scattered a bit more. In fact, I
believe you can photograph the UV bands with a
camera, provided that there are no optics in the
camera that filter UV light.
Yes, they do. A chemistry professor who
answered a question just like yours on the
internet says that you can see the ultraviolet
band in a black and white photograph of a rainbow
because the film is sensitive to UV light. I
haven't tried this myself, but maybe you can try
it at home! Next time you see a rainbow, take a
photograph using color film and take another using
black and white film and then compare the photos.
You should see an extra band in the black and
white photo. Just make sure that you use a camera
without a UV filter. Have fun!
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