Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: charli on 14/06/2021 06:18:18
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David would like to know:
"Does reflected light have different properties to sunlight, and could this be used in scientific applications?"
Do you have any reflections for David?
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Because mirrors are not perfect the amount of light reflected will be less than the original light. Also some frequencies will not be reflected changing the colour of the light.
However, there is one obvious application, that of using a curved mirror to focus the suns rays and create an area of intense heat. Look up solar furnace for more info
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One of the oldest applications of reflected light was to see at night.
- The Moon is usually above the horizon for part of the night
- The reflected light gives some limited night vision.
The property of interest here is that Moonlight is available at night, while Sunlight isn't.
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If objects didn't reflect light, they would be invisible.
Many objects will absorb some wavelengths, and reflect others, to create COLORS.
As mentioned above, mirrors have a special purpose reflecting light, and can used as telescope lenses. Many old microscopes had a mirror to reflect light into the slide and lens.
Cats and many animals have a Tapetum Lucidum in the eyes which reflects light back through the retina, thus doubling the light on the receptors, and the reason animal eyes are often so eerily bright at night.
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I don't know Clifford, but that's no news :)
Isn't black a absence of reflections for our receivers of 'light' (eyes), interpreted by our brains as being 'black'?
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ah, okay, got you. As in a totally dark room everything becomes invisible. But the fact is that 'black' do exist, and that we can see it, although as you point out, we can't.
(that would make for a nice zen riddle methinks.)
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Hi.
You have plenty of good answers already but there's no mention of polarisation yet.
Sometimes reflected light is polarised, while the original incident light had all possible polarisations fairly equally represented. This effect depends on the substance or interface from which reflection is occurring and sometimes on the angle of incidence with that interface.
Can this be put to scientific use? Well, some manufacturers of glasses for driving, produce glasses with polarising lenses and claim that they cut down "glare" from reflections. There are also glasses for fisherman that use polarising lenses to help them see through the water and cut down the reflection from the surface. NOTE: I'm not saying that either of these work well, only that there is some scientific basis for them.
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How about producing electricity with a power tower?