Even today, people sometimes incorrectly say that this is the case. Later scientists realised that if this were true, there would be more variation of sky colour with humidity or haze conditions than was actually observed, so they supposed correctly that the molecules of oxygen and nitrogen in the air are sufficient to account for the scattering.
The case was finally settled by Einstein in , who calculated the detailed formula for the scattering of light from molecules; and this was found to be in agreement with experiment. He was even able to use the calculation as a further verification of Avogadro's number when compared with observation.
The molecules are able to scatter light because the electromagnetic field of the light waves induces electric dipole moments in the molecules. If shorter wavelengths are scattered most strongly, then there is a puzzle as to why the sky does not appear violet, the colour with the shortest visible wavelength. The spectrum of light emission from the sun is not constant at all wavelengths, and additionally is absorbed by the high atmosphere, so there is less violet in the light.
Our eyes are also less sensitive to violet. That's part of the answer; yet a rainbow shows that there remains a significant amount of visible light coloured indigo and violet beyond the blue. The rest of the answer to this puzzle lies in the way our vision works. We have three types of colour receptors, or cones, in our retina. They are called red, blue and green because they respond most strongly to light at those wavelengths.
As they are stimulated in different proportions, our visual system constructs the colours we see. Response curves for the three types of cone in the human eye. When we look up at the sky, the red cones respond to the small amount of scattered red light, but also less strongly to orange and yellow wavelengths.
The green cones respond to yellow and the more strongly scattered green and green-blue wavelengths. Why does the blue fade towards the horizon? You might also like.
What weather conditions are typically associated with areas of high and low pressure? Read more. The properties and behaviour of light, and how it interacts with droplets of water, give rise to one of nature's most colourful meteorological events - the rainbow. As demonstrated by Sir Isaac Newton with a triangular prism, when white light passes through the prism it separates out into the colours of the rainbow. This experiment demonstrates that white light is composed of all the colours of visible light in roughly the same amounts.
These different colours have different wavelengths, and this affects how they interact with different substances. Violet and blue light have the shortest wavelengths and red light has the longest.
Find more astronomy videos and resources. Sunlight can be redirected by the air molecules and this is known as 'scattering'. The size of these molecules is much smaller than the wavelengths of visible light. The type of scattering that occurs is known as Rayleigh scattering named after Lord Rayleigh John William Strutt who discovered it. This type of scattering increases as the wavelength of light decreases, so blue light is scattered more than red light by the tiny air molecules in our atmosphere.
Sign-Up Here. Ada McVean B. General Science. AdaMcVean Leave a comment! Is it true that the Beatles wrote a song about LSD? Is it true that you cannot eat polar bear liver?
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