Why water is colourless

  • Thread starter gracy
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  • #1
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Here is the link which explains this.But i don't think it is right because according to the explanation given water should be black not colourless.http://kinooze.com/2012/09/09/why-is-water-colourless/I think water reflects light which is not in our visible range,right?
 

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  • #5
davenn
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This is the worse explanation I have ever seen. Water is colourless because it lets visible light pass through, without absorbing much.
Exactly !

its is noted that purified (distilled) water will have a slight blue tint to it

that last statement on the linked page is just so wrong .....
In case of water, almost all the colours are absorbed. No colour is reflected back, thus no colour reaches our eyes. That is how water appears to be without any colour.
if all the colours were absorbed then yes, it would be black

Dave
 
  • #6
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Exactly !

its is noted that purified (distilled) water will have a slight blue tint to it

that last statement on the linked page is just so wrong .....


if all the colours were absorbed then yes, it would be black

Dave
Ok can you please tell me if white color reflects infrared light also?
 
  • #7
Orodruin
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What your eye sees as white is a combination of light of wavelengths across the spectrum.
 
  • #8
davenn
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IT does to a better degree than say black

feel the difference in temperature between a white and a black painted car that is in the sun
 
  • #9
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IT does to a better degree than say black

feel the difference in temperature between a white and a black painted car that is in the sun
So the object which is reflecting most nearly all of the wavelength of visible spectrum (i.e white color object)will reflect infrared light also.right?
 
  • #10
DrClaude
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Ok can you please tell me if white color reflects infrared light also?
First, infrared is a big part of the electromagnetic spectrum, so there is not a single thing as infrared light. As davenn said, in general withe things will also show greater reflection of IR radiation, especially in the near IR. But you could, at least in principle, have a material that is white but still absorbs all IR radiation.
 
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  • #11
davenn
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great response :)
 
  • #12
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First, infrared is a big part of the electromagnetic spectrum, so there is not a single thing as infrared light. As davenn said, in general withe things will also show greater reflection of IR radiation, especially in the near IR. But you could, at least in principle, have a material that is white but still absorbs all IR radiation.
But white color object would reflect IR better than any other colored object say red or blue,is it right?
 
  • #13
Orodruin
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IT does to a better degree than say black

feel the difference in temperature between a white and a black painted car that is in the sun
You cannot say this a priori. The color of an object is (mainly) based on its interaction with light in the visible range.

The main part of the Sun's light is in the visible spectrum, which black absorbs and thus becomes warmer. You cannot draw a conclusion about the IR properties solely based on this, you would need a source mainly active in the IR spectrum.
 
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  • #14
DrClaude
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But white color object would reflect IR better than any other colored object say red or blue,is it right?
If its blue, probably, but if it is red, absolutely not! It is already reflecting in the red part of the spectrum, so it is probably also reflecting in the near IR.
 
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  • #15
davenn
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You cannot draw a conclusion about the IR properties solely based on this,
True and I didn't :)

DrClaude expanded on the theme well :)

First, infrared is a big part of the electromagnetic spectrum, so there is not a single thing as infrared light. As davenn said, in general withe things will also show greater reflection of IR radiation, especially in the near IR. But you could, at least in principle, have a material that is white but still absorbs all IR radiation.
 
  • #17
Orodruin
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True and I didn't :)

DrClaude expanded on the theme well :)
If you ask him to feel a black and white car in the Sun, this seems to imply that this is an argument for white reflecting more of the IR. It is an argument for white reflecting more visible light.

I agree DrClaude wrote it nicely.
 
  • #20
DaveC426913
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Okyou mean red color object reflects red color better than white color .
No, this is not true. White is reflecting all colours, including red.

A red object is as likely to reflect infra-red frequencies as a white object. It's all in the specifics of the pigment.
 

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