The discussion centers on the optical properties of water, specifically its colorlessness and transparency. Participants assert that water appears colorless because it allows visible light to pass through without significant absorption, contradicting claims that it should appear black. The conversation also touches on the reflection of light by different colors, particularly how white objects reflect infrared light better than darker colors, while emphasizing that the interaction of light with materials is complex and depends on specific wavelengths.
PREREQUISITESStudents of physics, environmental scientists, and anyone interested in the optical properties of materials and their interactions with light.
And what about reflection?color of object all depends on reflection,so water reflects..?DrClaude said:This is the worse explanation I have ever seen. Water is colourless because it let's visible light pass through, without absorbing much.
http://en.wikipedia.org/wiki/Electr.../File:Absorption_spectrum_of_liquid_water.png
Water is transparent.gracy said:And what about reflection?color of object all depends on reflection,so water reflects..?
DrClaude said:This is the worse explanation I have ever seen. Water is colourless because it let's visible light pass through, without absorbing much.
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.
Ok can you please tell me if white color reflects infrared light also?davenn said: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
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?davenn said: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
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.gracy said:Ok can you please tell me if white color reflects infrared light also?
But white color object would reflect IR better than any other colored object say red or blue,is it right?DrClaude said: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.
davenn said: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
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.gracy said:But white color object would reflect IR better than any other colored object say red or blue,is it right?
Orodruin said:You cannot draw a conclusion about the IR properties solely based on this,
DrClaude said: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.
Okyou mean red color object reflects red color better than white color .Thanks for great explanation.Can you please look at this link .http://io9.com/5903956/the-physics-that-explain-why-you-should-wear-black-this-summer.DrClaude said: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.
davenn said:True and I didn't :)
DrClaude expanded on the theme well :)
If it is hot out where is your body heat going to be relative to the air around you? On a comfortable spring day perhaps black might keep you cooler...gracy said:
Bedouins wear black in the desert, and there is a reason:jerromyjon said:If it is hot out where is your body heat going to be relative to the air around you? On a comfortable spring day perhaps black might keep you cooler...
No, this is not true. White is reflecting all colours, including red.gracy said:Okyou mean red color object reflects red color better than white color .