I know that the the light gets reflected off them but the light that gets reflected is the light of the source. So, how are we able to see them if they don't emit light?
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This is actually a good question.
If you think about the way 'reflection' is normally explained, you would expect that an object would be much much brighter if you looked at the 'bounce' angle of the light - at just the area where the light is reflected 'to'. But objects do not appear that way, rather they appear to sort of glow with their own light.
And they do!
In Quantum Mechanics, we say that all of the radiation, all of the photons that hit a surface are absorbed by the electrons of the molecules of that surface. The electrons absorb the energy of the photon and jump to higher energy states. And the photons no longer exist.
Then, after a very VERY short interval of time, the electron drops energy states and emits a photon, and that photon is what we see. But since the photon is emitted by the electron that is a part of the molecules of the material, it appears to be originating there - which it is. So it looks like the color is coming from the material, and that it is not 'reflected' after all.
Depending on how electrons are configured in the molecules, some are able to jump energy levels that correspond to certain colors and some are not, and if they are none that can make a certain jump, the energy may be released in several jumps, so the original color is lost, and the object will not emit that color. This gets more complicated from here, but this is the basic idea.
It is a bit astonishing that, while we have known about this since the early 1900s, you still find the old explanation, even in college textbooks!
If you think about the way 'reflection' is normally explained, you would expect that an object would be much much brighter if you looked at the 'bounce' angle of the light - at just the area where the light is reflected 'to'. But objects do not appear that way, rather they appear to sort of glow with their own light.
And they do!
In Quantum Mechanics, we say that all of the radiation, all of the photons that hit a surface are absorbed by the electrons of the molecules of that surface. The electrons absorb the energy of the photon and jump to higher energy states. And the photons no longer exist.
Then, after a very VERY short interval of time, the electron drops energy states and emits a photon, and that photon is what we see. But since the photon is emitted by the electron that is a part of the molecules of the material, it appears to be originating there - which it is. So it looks like the color is coming from the material, and that it is not 'reflected' after all.
Depending on how electrons are configured in the molecules, some are able to jump energy levels that correspond to certain colors and some are not, and if they are none that can make a certain jump, the energy may be released in several jumps, so the original color is lost, and the object will not emit that color. This gets more complicated from here, but this is the basic idea.
It is a bit astonishing that, while we have known about this since the early 1900s, you still find the old explanation, even in college textbooks!
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All objects are seen due to the reflected light bouncing of them. The colour of an object is due to the absorption or reflection of light. If we see something that is red for example, this means that all wavelengths of light are absorbed with the exception of red, which is reflected, thus we see a red object.
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