People often mistakenly believe that the sky’s hue comes from ocean waves; however, this is incorrect: its hue results from how atmospheric molecules scatter light and reflect it back onto Earth’s surface.
Light passing through the atmosphere tends to scatter more readily in blue and violet wavelengths due to their frequencies being closer to those that resonate naturally with air molecules and atoms.
Rayleigh Scattering
Rayleigh scattering, which occurs when sunlight passes through an atmosphere, gives rise to the blue hues we associate with skies. Light interacting with molecules scatters across all directions; shorter wavelengths (like blue end of spectrum light ) is scattered more strongly due to molecules being smaller than visible light wavelengths.
John Tyndall conducted a famous experiment in 1859 that established that the sky is blue due to scattering phenomena; some still believe otherwise. Tyndall conducted this test by shining white light through clear liquid with small particles suspended, and observed its reddening as it passed through the liquid. Sir Arthur Rayleigh later verified this discovery by showing how scattering is directly proportional to fourth power of wavelength for sufficiently small particles.
Rayleigh scattering also affects the ocean, but for different reasons. The shade of its blue depends on depth – deeper waters tend to have darker tones while shallower ones have lighter ones. From space, planet Earth appears blue due to this process as well, though only for regions covered by water bodies.
The colors of oceans and skies vary slightly in different parts of the world, with tropical regions having lighter waters than temperate zones due to less-saline continental shelf waters being closer.
The blue hues found in oceans and skies are further highlighted by being more saturated than other colors such as red or violet, due to the molecules in air easily scattering short wavelengths of blue and violet while long wavelengths like red and violet tend to absorb them more readily – hence why daylight sky appears predominantly blue while sunset and sunrise appear as reddish glows.
Water Absorption
The ocean’s hue derives from how water molecules absorb and reflect different wavelengths of light; longer red and orange wavelengths penetrate deep into its depths while violet wavelengths can escape to reach our eyes as blue. When weather conditions are calm or surface lakes or oceans are clear, blue hues become readily apparent in their waters; yet this phenomenon doesn’t explain why skies appear blue – rather it has more to do with interaction between air molecules and our eyes than anything else!
Sunlight that enters the atmosphere must traverse it in order to reach our eyes, and as it does so it becomes scattered in all directions – a process known as bulk attenuation that occurs faster for higher-frequency colors such as blue and violet than for lower frequency colors like red and yellow. As sunlight passes through this atmospheric medium, its blue-violet components tend to scatter more than their red-yellow counterparts, leading to what makes sky appear bluer.
Our eyes have three types of cone cells which allow us to detect and interpret these scattered wavelengths – green, blue and red cone cells are specifically tailored to detect different frequencies of light. Red cones stimulated by strongly scattered indigo and violet wavelengths are responsible for giving the sky its blue tint, while blue and green cones stimulated by less-diffuse indigo and violet wavelengths are responsible for giving clouds their signature blue hue. Rayleigh Scattering provides the key explanation for all this. First put forward in 1871 by Lord Rayleigh, it asserts that scattered light intensity varies inversely with frequency to the fourth power and that shorter wavelengths (like blue) scatter more readily than longer ones ( like violet). As you move away from the horizon, where atmospheric density is thickest, the sky becomes paler as less blue light reaches your eyes. If you continued rising into the atmosphere, eventually it would begin to look black as light was absorbed by more and more molecules and eventually begin to obscure any further vision of blue sky.
Water Reflection
Light arriving in Earth’s atmosphere is scattered in all directions by molecules comprising air. Blue hues tend to be scattered more widely than others, which explains why we generally see blue skies.
But what happens when light hits water? As light passes through it, some wavelengths get absorbed by molecules within it – this explains why even on clear days the sea appears bluer.
Refracted lightwaves return to our eyes in various wavelengths; blue wavelengths are especially strong. As such, bodies of water such as oceans or glasses of water may appear different shades of blue depending on its depth.
Deeper bodies of water typically appear darker and deeper in color than shallower waters, reflecting how deeper bodies absorb more red wavelengths, leaving behind blue.
Water can take on various colors depending on its constituents, for instance when algae or plant life absorb and scatter yellow wavelengths of light; this creates a greenish tint, giving the oceans their characteristic hue after storms.
It explains why, when looking at an object on the surface of water, it appears shorter than actual size; this is because its length is divided by the speed of waves causing its reflection.
White light contains all of the colors of the rainbow, yet our eyes only detect certain wavelengths more strongly than others. Our brain interprets those signals as specific colors – for instance, red cones in our eyes respond more strongly when exposed to scattered red wavelengths than un-scattered blue ones; we use these signals from both eyes and brain to perceive sky as blue.
Light Reflection
One popular explanation for why the sky is blue is because water reflects it back. While this may be partially true, sunlight passes through our atmosphere where air molecules scatter it in all directions – with blue wavelengths being scattered more strongly than red or green wavelengths; hence why we perceive our sky to be blue.
Light that bounces off of the ocean’s surface does likewise. While its blue light reflects back, its red wavelengths absorb and filter away, leaving only blue rays for us to view – hence why the ocean appears deep blue while sky colors range between lighter hues of blue.
No matter if we are discussing waves or particles, the principle remains the same. A smooth pool of water reflects light to create an accurate reflection of its surroundings; when something heavy drops into it though, waves are formed which disperse light in all directions and form images similar to what can be seen when winds and storms are blowing heavily over an ocean or skyscape.
This same effect occurs when sunlight hits Earth. It is no coincidence that when sunny, the sky appears bluer; however, explaining why it changes color when cloudy or rainy conditions prevail is more challenging.
Tyndall and Rayleigh agreed that the color of the sky depends on humidity or dust haze in the air; however, they differed on its cause: Tyndall thought the haze contained droplets of water while Rayleigh believed it contained gases such as oxygen and nitrogen.
At any moment in time, it’s actually the combination of these gases that give the sky its distinctively blue appearance. On cloudy or rainy days, when there is haze filled with particles larger than blue and red wavelengths emitted from blue lights and red lights that emit them, which creates white-tinged haze; when conditions clear up completely however, all wavelengths are scattered evenly and thus give off blue hues, giving this particular hue to the sky.