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Thread: Question about H20

  1. #1 Question about H20 
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    Say your at a party and spill water all over your shirt, it apears that the water makes the shirt "darker"... So why does something so transparent as water make something darker?

    Say you look in a glass of water, it is clear, you can see right through the water. But when you put lots of this water into a giant pool, you can't see through it as easily, why?


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  3. #2  
    Forum Freshman Jinn's Avatar
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    As far as the shirt question. I may be way over complicating this but since the shirt has absorbed the water it isn't the same density as the rest, and light reflects differently. thus the darkening in color.

    And as for the pool question, i think it would be the sheer mass of the watter. with so much water refracting and reflecting light it makes it "more difficult" to see through that in a simple glass of water.


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  4. #3  
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    I think the darkness of wet fabric is due to the different refractive index of water versus the fabric. The dry fabric has a high index and reflects more light. The water forms a film of a lower refractive index which allows some light to enter then some of it gets absorbed.

    You can see through pretty deep water if the surface is calm and the water is very clean.
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    The swimming pool water is dirty, causing light to eventually be eliminated. The number of impurities in a glass of water do not have enough time to effect the light, while in a pool, it has over 30X the effect do to the number and amount of impurities it has to travel through. It like holding up a really thin sheet of paper and shinning a flash light onto it; the more pieces of paper you add, the more the light gets filtered out, until it is all being absorbed. The question is:

    What if you had a tank of completely pure distilled water a mile deep, could you see through it perfectly?

    Why is deep water blue? Is it only a basic quantum mechanical property of the water, or is it due to impurities?
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

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    Water is actually slighty blue. It just appears transparent in small amounts.
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  7. #6  
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    If something with all pigments appears black, and something with no pigments appears white, and everything inbetween is the visible spectrum. Where do transparent materials lie?

    Also
    In clean air without condensation etc... You can see right through it, but it's not black. But like in open space, with no air, it is black, and the light, just like in the air's case travels right through.

    Thank you for all your responses!
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  8. #7  
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    Quote Originally Posted by rancidchickn
    Water is actually slighty blue. It just appears transparent in small amounts.
    Same reason why the sky is blue I assume?
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    [quote="pianoforte"]
    Quote Originally Posted by rancidchickn
    Same reason why the sky is blue I assume?
    The sky is blue because dust (and nitrogen) in the air scatter blue light, so a lot of the blue light that would have "grazed" the earth's atmosphere but not actually intersected with the ground gets scattered in random directions. Some of it gets scattered downward, so it looks like there is a blue light source above you.

    Water is blue because it absorbs red light. I believe it has to do with the red light being absorbed by hydrogen bonds.
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  10. #9  
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    Where is the blue light in space coming from? I thought all light coming from the sun is white. Do you also mean that a part of the atmosphere absorbs the other colors, leaving only blue left?
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

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    White visible light is made up of the colors of the rainbow. The atmosphere refracts light in the same way a prism does. Blue light bends the most towards the surface, so that is the color we see. When the angle of incidence changes enough, as in sunrise and sunset, the other colors are bent enough for them to show up. Pretty colors! :? :wink:
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  12. #11  
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    Quote Originally Posted by KALSTER
    White visible light is made up of the colors of the rainbow. The atmosphere refracts light in the same way a prism does. Blue light bends the most towards the surface, so that is the color we see. When the angle of incidence changes enough, as in sunrise and sunset, the other colors are bent enough for them to show up. Pretty colors! :? :wink:
    Not exactly. The atmosphere doesn't "bend" the path of the light in a predictable way like a prism, it just constantly scatters blue light in random directions. When the sun is setting the light looks red because there is lack of blue light - most of the blue light that would have been coming directly at you has now been scattered off in another direction, so all the remaining colors that haven't been scattered and are coming directly at you look red.
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    Quote Originally Posted by Scifor Refugee
    Quote Originally Posted by KALSTER
    White visible light is made up of the colors of the rainbow. The atmosphere refracts light in the same way a prism does. Blue light bends the most towards the surface, so that is the color we see. When the angle of incidence changes enough, as in sunrise and sunset, the other colors are bent enough for them to show up. Pretty colors! :? :wink:
    Not exactly. The atmosphere doesn't "bend" the path of the light in a predictable way like a prism, it just constantly scatters blue light in random directions. When the sun is setting the light looks red because there is lack of blue light - most of the blue light that would have been coming directly at you has now been scattered off in another direction, so all the remaining colors that haven't been scattered and are coming directly at you look red.
    I stand corrected I should make a point of adding "IMHO" or "I think" after all my posts from now on.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    What are the quantum properties of light refraction in the atmosphere? As in, how does it work on the atomic level? I can see how a prism works, but I can't see how gases can have the same effect.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

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    The effect is known as Rayleigh scattering.
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    If something with all pigments appears black, and something with no pigments appears white, and everything inbetween is the visible spectrum. Where do transparent materials lie?
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  17. #16  
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    Quote Originally Posted by Raymond K
    If something with all pigments appears black, and something with no pigments appears white, and everything inbetween is the visible spectrum. Where do transparent materials lie?
    Transparent things don't absord or scatter light well, so most of the light just passes through them.
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