Why is the Sky Blue and What Causes This Color?

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Discussion Overview

The discussion revolves around the question of why the sky appears blue, exploring the underlying physical principles, particularly Rayleigh scattering, and the relationship between the color of the sky and the color of water. Participants share various explanations and challenge each other's claims regarding the nature of light scattering and the intrinsic color of water.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants explain that sunlight is scattered by gases and particles in the atmosphere, with blue light being scattered more than other colors due to its shorter wavelength.
  • One participant notes that the sky is not uniformly blue, mentioning that it appears bluer directly overhead and lighter towards the horizon.
  • Another participant references Rayleigh's scattering law, stating that scattering is inversely proportional to the fourth power of the wavelength, leading to different colors being scattered to varying degrees.
  • There is a challenge regarding the claim that pure water is intrinsically blue, with some participants expressing skepticism about this assertion.
  • A participant provides a link to a Wikipedia article on the color of water, indicating interest in verifying claims about water's color.
  • Another participant expresses relief in finding that their perception of water's color aligns with the information presented in the article, while still acknowledging the need to assume the accuracy of the source.

Areas of Agreement / Disagreement

Participants express differing views on the intrinsic color of water and its relation to the color of the sky, leading to an unresolved debate about these aspects. There is no consensus on the nature of water's color, and the discussion remains open-ended.

Contextual Notes

Some claims depend on specific definitions of color and scattering, and the discussion does not resolve the nuances of these concepts. Additionally, the relationship between atmospheric density and scattering is mentioned but not fully explored.

wasi-uz-zaman
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hi ,
please tell me why sky is blue?
 
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wasi-uz-zaman said:
hi ,
please tell me why sky is blue?

Sunlight is scattered by gases and particles in the atmosphere. Blue light is essentially a shorter, smaller wave, and is therefore typically more scattered than the other colors.

If you look more closely, you'd see its not REALLY "blue". Its bluer straight up, but gets lighter and whiter towards the horizon, etc.

This is related to why water can look blue too.
 
If you Google "why sky is blue" you get 786,000,000 hits. The first page is all remarkably good. If there is something you still don't understand after reading that, you might post a specific question here.
 
Tea Jay said:
This is related to why water can look blue too.

not quite. Pure water appears blue because it is intrinsically blue.
 
wasi-uz-zaman said:
hi ,
please tell me why sky is blue?

No, not in general but at times , yes... The law is Raleigh's Scattering law.
Scattering \propto1/λ4

As wavelength increases scattering decreases.
Wavelength increases as we go from right to left of the word : VIBGYOR

We know that the density of atmosphere decreases as we go up higher and higher. By Raleigh's scattering law the diameter of the particle must be greater than the wavelength of a particular colour. So violet is scattered the most in upper region of atmosphere and red the least in lower region. This is why we see somewhat orange colour in atmosphere at times of dusk mainly ( and little at dawn). The blue colour is scattered at upper regions mainly because of shorter wavelength because light is both wave like and particulate. The particulate size of blue is less.
 
Bloodthunder said:
not quite. Pure water appears blue because it is intrinsically blue.

You are saying that distilled water is blue? I don't believe that.
 
phinds said:
You are saying that distilled water is blue? I don't believe that.

http://en.m.wikipedia.org/wiki/Color_of_water
 
Bloodthunder said:
http://en.m.wikipedia.org/wiki/Color_of_water[/QUOTE]

Very interesting. Thanks for that. I was glad to see that my eyes were not deceiving me on small quantities, but I see that you are fundamentally right (assuming, as one always must assume, that the wiki is right --- but in this case iit SOUNDS right)
 
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