An engaging article can enlighten and educate your target audience, as well as drive traffic to your website and convert customers.
Isaac Newton proved with his prism that white light contains all of the colors visible spectrum, yet each hue has its own wavelength: violet and blue wavelengths are shorter while red’s have longer ones.
John Tyndall
John Tyndall (not to be confused with the late British neo-Nazi leader of the same name) was an Irish physicist best known for his discovery that helped explain why the sky is blue. Additionally, he was an adept mountaineer and gifted communicator of science; writing over eighty five scientific papers while contributing significantly in glaciology, meteorology and bacteriology research.
Born in Leighlinbridge in County Carlow and initially working at the Ordnance Survey of Ireland as a draftsman, he later relocated to England in 1852 where, through hard work and persistence, he quickly rose through the ranks to become Professor of Natural Philosophy at Royal Institution London.
Tyndall had an international reputation as an experimental scientist who did not shy away from controversy. He advocated that religion filled emotional needs while science offered reliable information and would eventually replace it as the dominant mode.
He focused not only on how light was scattered but why. He was the first to suggest that the reason the sky appears blue is due to light scattering off small particles more often than off long, red wavelengths; later confirmed by Lord Rayleigh who discovered exactly how this phenomenon worked.
Tyndall was an outstanding science teacher, disseminating knowledge to laymen through hundreds of public lectures he gave on various subjects as well as writing extensively about science. He strongly supported evolutionary theory as well as Louis Pasteur’s germ theory.
He married later and died at 73 from an accidental overdose of chloral hydrate given by his wife Louisa, although not religious he believed strongly in science’s ability to change our world for the better. Louisa collected massive amounts of material on him but never published her biography despite efforts from Louisa herself to write one; Tyndall left behind an enormous legacy of scientific discovery reminiscent of Faraday and many Victorian pioneers before him.
Rayleigh Scattering
Many of us might assume that the sky is blue because the sun reflects off of the ocean; however, its true meaning lies further beneath. Light is scattered by gases and particles present in the atmosphere – this phenomenon was first identified by John Tyndall in 1859 and named Rayleigh Scattering.
Tyndall conducted experiments to detect contaminants remaining in the purified air used for infrared research, and noticed that bright light scattering off nanoscale particulates appeared faintly blue-tinged. He speculated that sky must also have this hue, so set out on his mission to discover its source.
As sunlight passes through the atmosphere, it interacts with gasses and particles such as Nitrogen and Oxygen molecules that are much smaller than wavelengths of light; this causes it to scatter widely; short wavelengths like blue and violet tend to scatter more frequently than longer ones such as red ones – giving rise to its characteristic blue hue.
This phenomenon also explains why the sky seems brightest overhead before gradually dimming toward the horizon; more of the Sun’s light has had time to diffuse into Earth’s atmosphere and dissipate as you approach closer to its surface.
Tyndall experimented with various materials throughout his career, from food and water to glass and glaciers. A keen mountaineer, Tyndall spent considerable time hiking in the Alps which likely inspired his interest in atmospheric phenomena. Tyndall combined mountaineering knowledge with physics knowledge in creating practical tests for measuring air pressure and temperature by shining white light through clear fluids with more of one substance added over time, until eventually its effects appeared to cause its color change when seen directly or from side or end views.
Tyndall eventually recognized that the coloration of beams he saw depended on the size of particle that was scattering them; larger particles tended to scatter more. He came to believe that gas and dust particles were scattering sunlight more heavily, leading him to conclude that sunbeams were scattered by gas-rich clouds creating blue hues in the sky.
The Tyndall Effect
John Tyndall was an experimental scientist renowned for discovering many phenomena from magnetic effects to atomic structure. Additionally, his love of nature led him to spend much time climbing in the Alps and investigating glaciers; from this activity came Tyndall’s realization that blue light scatters more readily when reaching Earth’s atmosphere than other colors; this phenomenon became known as the Tyndall effect and helps explain why our skies appear blue when gazing skyward.
Light reaching Earth’s atmosphere is scattered in all directions by gases and particles in the air, particularly shorter wavelengths such as blue and violet light whose wavelengths have more frequency of scattering due to oxygen and nitrogen molecules hitting each other and dispersing light as they collide. Longer wavelengths like red and orange don’t seem as affected by this effect so tend to pass more easily through our atmosphere.
As the sky contains an array of gases and particles, its colors vary considerably throughout the rainbow spectrum. You will notice that its colors peak overhead before gradually diminishing into more muted tones nearer to the horizon due to light having to travel further distances before being dispersed more times; making its brilliance somewhat duller as it passes over further distances and has more chances to dissipate into darkness.
Tyndall was an accomplished mountaineer as well as an esteemed physicist. Having assisted Michael Faraday with his work on magnetism, he turned his focus towards scattering of light experiments. These ultimately led him to demonstrate that gases absorb heat by heating a copper cube filled with boiling water – something which later inspired his research on greenhouse effect and showed the Earth’s atmosphere can trap energy from sunlight.
Rayleigh developed in 1871 a formula describing some interactions, based on the principle that scattered light intensity decreases as its wavelength changes inversely – this formula has become widely used by scientists for predicting scattered light intensity when certain gases are present.
Why is the sky blue?
One of the most frequently asked questions about the sky is why it is blue. To explain this phenomenon, let’s turn to light science: as sunlight hits Earth’s atmosphere it scatters – longer wavelengths such as red and orange light tend to get absorbed by air molecules while blue-violet light scatters less – leading to much of our sunlight being visible as blue light passing through.
Imagine shining a bright white beam into a tank filled with clear water containing small particles suspended throughout it; these will scatter and mix the light, but blue wavelengths will be scattered more than red or orange ones; this is Tyndall’s basic explanation for his findings.
As light hits Earth’s atmosphere, it is also absorbed by its gases like nitrogen and oxygen, which absorb some of the light before reflecting some back out to form new waves of color that reach us through our eyes. Blue wavelengths tend to scatter more easily than others; thus making up most of what reaches our eyes.
Daylight illuminates our sky in its most vivid blue form; at nighttime however, sunlight must pass through more atmosphere before reaching you and thus softens its hue to form more of a pale hue.
Have you noticed how the sky appears darker near the horizon and more bluish-violet higher up? That is due to lower air molecules at higher elevations; less molecules scatter short wavelengths of blue more easily than others.
As you ascend into the atmosphere, the intensity of blue fades as molecules scatter light less efficiently; eventually it disappears altogether at higher altitudes, turning the sky black due to no more molecules scattering it around. Astronauts aboard Blue Origin spacecraft witness Earth’s atmosphere slowly dissipating as they travel upward into space; similar effects make open water appear blue on other planets without atmospheres like Mars and Luna as well as explain why outer space skies appear black.