A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun. Rainbows can be full circles. However, the observer normally sees only an arc formed by illuminated droplets above the ground, and centered on a line from the sun to the observer's eye. In a primary rainbow, the arc shows red on the outer part and violet on the inner side. This rainbow is caused by light being refracted when entering a droplet of water, then reflected inside on the back of the droplet and refracted again when leaving it. In a double rainbow, a second arc is seen outside the primary arc, and has the order of its colors reversed, with red on the inner side of the arc. This is caused by the light being reflected twice on the inside of the droplet before leaving it.
1 Overview 2 Visibility 3 Number of colours in spectrum or rainbow 4 Explanation
4.1 Mathematical derivation
5.1 Multiple rainbows 5.2 Twinned rainbow 5.3 Full-circle rainbow 5.4 Supernumerary rainbows 5.5 Reflected rainbow, reflection rainbow 5.6 Monochrome rainbow 5.7 Higher-order rainbows 5.8 Rainbows under moonlight 5.9 Fogbow 5.10 Circumhorizontal and circumzenithal arcs 5.11 Rainbows on Titan 5.12 Rainbows with different materials
6 Scientific history 7 Experiments 8 Culture 9 Image gallery 10 See also 11 Notes 12 References 13 External links
Image of the end of a rainbow at Jasper National Park
A rainbow is not located at a specific distance from the observer, but comes from an optical illusion caused by any water droplets viewed from a certain angle relative to a light source. Thus, a rainbow is not an object and cannot be physically approached. Indeed, it is impossible for an observer to see a rainbow from water droplets at any angle other than the customary one of 42 degrees from the direction opposite the light source. Even if an observer sees another observer who seems "under" or "at the end of" a rainbow, the second observer will see a different rainbow—farther off—at the same angle as seen by the first observer. Rainbows span a continuous spectrum of colours. Any distinct bands perceived are an artefact of human colour vision, and no banding of any type is seen in a black-and-white photo of a rainbow, only a smooth gradation of intensity to a maximum, then fading towards the other side. For colours seen by the human eye, the most commonly cited and remembered sequence is Newton's sevenfold red, orange, yellow, green, blue, indigo and violet, remembered by the mnemonic, Richard Of York Gave Battle In Vain (ROYGBIV). Rainbows can be caused by many forms of airborne water. These include not only rain, but also mist, spray, and airborne dew.
Rainbows can form in mist, such as that of a waterfall.
Rainbows may form in the spray created by waves (called spray bows).
Rainbows can be observed whenever there are water drops in the air and
sunlight shining from behind the observer at a low altitude angle.
Because of this, rainbows are usually seen in the western sky during
the morning and in the eastern sky during the early evening. The most
spectacular rainbow displays happen when half the sky is still dark
with raining clouds and the observer is at a spot with clear sky in
the direction of the sun. The result is a luminous rainbow that
contrasts with the darkened background. During such good visibility
conditions, the larger but fainter secondary rainbow is often visible.
It appears about 10° outside of the primary rainbow, with inverse
order of colours.
The rainbow effect is also commonly seen near waterfalls or fountains.
In addition, the effect can be artificially created by dispersing
water droplets into the air during a sunny day. Rarely, a moonbow,
lunar rainbow or nighttime rainbow, can be seen on strongly moonlit
nights. As human visual perception for colour is poor in low light,
moonbows are often perceived to be white.
It is difficult to photograph the complete semicircle of a rainbow in
one frame, as this would require an angle of view of 84°. For a
35 mm camera, a wide-angle lens with a focal length of 19 mm
or less would be required. Now that software for stitching several
images into a panorama is available, images of the entire arc and even
secondary arcs can be created fairly easily from a series of
From above the earth such as in an aeroplane, it is sometimes possible
to see a rainbow as a full circle. This phenomenon can be confused
with the glory phenomenon, but a glory is usually much smaller,
covering only 5–20°.
The sky inside a primary rainbow is brighter than the sky outside of
the bow. This is because each raindrop is a sphere and it scatters
light over an entire circular disc in the sky. The radius of the disc
depends on the wavelength of light, with red light being scattered
over a larger angle than blue light. Over most of the disc, scattered
light at all wavelengths overlaps, resulting in white light which
brightens the sky. At the edge, the wavelength dependence of the
scattering gives rise to the rainbow.
Red Orange Yellow Green Blue Indigo Violet
Newton, who admitted his eyes were not very critical in distinguishing colours, originally (1672) divided the spectrum into five main colours: red, yellow, green, blue and violet. Later he included orange and indigo, giving seven main colours by analogy to the number of notes in a musical scale. Newton chose to divide the visible spectrum into seven colours out of a belief derived from the beliefs of the ancient Greek sophists, who thought there was a connection between the colours, the musical notes, the known objects in the Solar System, and the days of the week.
According to Isaac Asimov, "It is customary to list indigo as a color lying between blue and violet, but it has never seemed to me that indigo is worth the dignity of being considered a separate color. To my eyes it seems merely deep blue." The colour pattern of a rainbow is different from a spectrum, and the colours are less saturated. There is spectral smearing in a rainbow owing to the fact that for any particular wavelength, there is a distribution of exit angles, rather than a single unvarying angle. In addition, a rainbow is a blurred version of the bow obtained from a point source, because the disk diameter of the sun (0.5°) cannot be neglected compared to the width of a rainbow (2°). The number of colour bands of a rainbow may therefore be different from the number of bands in a spectrum, especially if the droplets are particularly large or small. Therefore, the number of colours of a rainbow is variable. If, however, the word rainbow is used inaccurately to mean spectrum, it is the number of main colours in the spectrum. The question of whether everyone sees seven colours in a rainbow is related to the idea of Linguistic relativity. Suggestions have been made that there is universality in the way that a rainbow is perceived. However, more recent research suggests that the number of distinct colours observed and what these are called depend on the language that one uses with people whose language has fewer colour words seeing fewer discrete colour bands. Explanation
When sunlight encounters a raindrop, part of the light is reflected
and the rest enters the raindrop. The light is refracted at the
surface of the raindrop. When this light hits the back of the
raindrop, some of it is reflected off the back. When the internally
reflected light reaches the surface again, once more some is
internally reflected and some is refracted as it exits the drop. (The
light that reflects off the drop, exits from the back, or continues to
bounce around inside the drop after the second encounter with the
surface, is not relevant to the formation of the primary rainbow.) The
overall effect is that part of the incoming light is reflected back
over the range of 0° to 42°, with the most intense light at
42°. This angle is independent of the size of the drop, but does
depend on its refractive index. Seawater has a higher refractive index
than rain water, so the radius of a "rainbow" in sea spray is smaller
than a true rainbow. This is visible to the naked eye by a
misalignment of these bows.
The reason the returning light is most intense at about 42° is that
this is a turning point – light hitting the outermost ring of the
drop gets returned at less than 42°, as does the light hitting the
drop nearer to its centre. There is a circular band of light that all
gets returned right around 42°. If the sun were a laser emitting
parallel, monochromatic rays, then the luminance (brightness) of the
bow would tend toward infinity at this angle (ignoring interference
effects). (See Caustic (optics).) But since the sun's luminance is
finite and its rays are not all parallel (it covers about half a
degree of the sky) the luminance does not go to infinity. Furthermore,
the amount by which light is refracted depends upon its wavelength,
and hence its colour. This effect is called dispersion.
We can determine the perceived angle which the rainbow subtends as
Given a spherical raindrop, and defining the perceived angle of the
rainbow as 2φ, and the angle of the internal reflection as 2β, then
the angle of incidence of the sun's rays with respect to the drop's
surface normal is 2β − φ. Since the angle of refraction is β,
sin(2β − φ) = n sin β,
where n = 1.333 is the refractive index of water. Solving for φ, we get
φ = 2β − arcsin(n sin β).
The rainbow will occur where the angle φ is maximum with respect to the angle β. Therefore, from calculus, we can set dφ/dβ = 0, and solve for β, which yields
− 1 +
displaystyle beta _ text max =cos ^ -1 left( frac 2 sqrt -1+n^ 2 sqrt 3 n right)approx 40.2^ circ
Substituting back into the earlier equation for φ yields 2φmax ≈ 42° as the radius angle of the rainbow. Variations Multiple rainbows "Double rainbow" redirects here. For other uses, see Double Rainbow.
Double rainbow created in the mist of Niagara Falls
Secondary rainbows are caused by a double reflection of sunlight
inside the raindrops, and are centred on the sun itself. They are
about 127° (violet) to 130° (red) wide. Since this is more than
90°, they are seen on the same side of the sky as the primary
rainbow, about 10° above it at apparent angles of 50–53°. As a
result of the "inside" of the secondary bow being "up" to the
observer, the colours appear reversed compared to the primary bow. The
secondary rainbow is fainter than the primary because more light
escapes from two reflections compared to one and because the rainbow
itself is spread over a greater area of the sky. Each rainbow reflects
white light inside its coloured bands, but that is "down" for the
primary and "up" for the secondary. The dark area of unlit sky
lying between the primary and secondary bows is called Alexander's
Alexander of Aphrodisias
Meanwhile, the even rarer case of a rainbow split into three branches was observed and photographed in nature. Full-circle rainbow In theory, every rainbow is a circle, but from the ground, only its upper half can be seen. Since the rainbow's centre is diametrically opposed to the sun's position in the sky, more of the circle comes into view as the sun approaches the horizon, meaning that the largest section of the circle normally seen is about 50% during sunset or sunrise. Viewing the rainbow's lower half requires the presence of water droplets below the observer's horizon, as well as sunlight that is able to reach them. These requirements are not usually met when the viewer is at ground level, either because droplets are absent in the required position, or because the sunlight is obstructed by the landscape behind the observer. From a high viewpoint such as a high building or an aircraft, however, the requirements can be met and the full-circle rainbow can be seen. Like a partial rainbow, the circular rainbow can have a secondary bow or supernumerary bows as well. It is possible to produce the full circle when standing on the ground, for example by spraying a water mist from a garden hose while facing away from the sun. A circular rainbow should not be confused with the glory, which is much smaller in diameter and is created by different optical processes. In the right circumstances, a glory and a (circular) rainbow or fog bow can occur together. Another atmospheric phenomenon that may be mistaken for a "circular rainbow" is the 22° halo, which is caused by ice crystals rather than liquid water droplets, and is located around the sun (or moon), not opposite it. Supernumerary rainbows
Contrast-enhanced photograph of a rainbow with additional supernumerary bands inside the primary bow
In certain circumstances, one or several narrow, faintly coloured bands can be seen bordering the violet edge of a rainbow; i.e., inside the primary bow or, much more rarely, outside the secondary. These extra bands are called supernumerary rainbows or supernumerary bands; together with the rainbow itself the phenomenon is also known as a stacker rainbow. The supernumerary bows are slightly detached from the main bow, become successively fainter along with their distance from it, and have pastel colours (consisting mainly of pink, purple and green hues) rather than the usual spectrum pattern. The effect becomes apparent when water droplets are involved that have a diameter of about 1 mm or less; the smaller the droplets are, the broader the supernumerary bands become, and the less saturated their colours. Due to their origin in small droplets, supernumerary bands tend to be particularly prominent in fogbows. Supernumerary rainbows cannot be explained using classical geometric optics. The alternating faint bands are caused by interference between rays of light following slightly different paths with slightly varying lengths within the raindrops. Some rays are in phase, reinforcing each other through constructive interference, creating a bright band; others are out of phase by up to half a wavelength, cancelling each other out through destructive interference, and creating a gap. Given the different angles of refraction for rays of different colours, the patterns of interference are slightly different for rays of different colours, so each bright band is differentiated in colour, creating a miniature rainbow. Supernumerary rainbows are clearest when raindrops are small and of uniform size. The very existence of supernumerary rainbows was historically a first indication of the wave nature of light, and the first explanation was provided by Thomas Young in 1804. Reflected rainbow, reflection rainbow
Reflection rainbow (top) and normal rainbow (bottom) at sunset
When a rainbow appears above a body of water, two complementary mirror bows may be seen below and above the horizon, originating from different light paths. Their names are slightly different. A reflected rainbow may appear in the water surface below the horizon. The sunlight is first deflected by the raindrops, and then reflected off the body of water, before reaching the observer. The reflected rainbow is frequently visible, at least partially, even in small puddles. A reflection rainbow may be produced where sunlight reflects off a body of water before reaching the raindrops (see diagram and ), if the water body is large, quiet over its entire surface, and close to the rain curtain. The reflection rainbow appears above the horizon. It intersects the normal rainbow at the horizon, and its arc reaches higher in the sky, with its centre as high above the horizon as the normal rainbow's centre is below it. Due to the combination of requirements, a reflection rainbow is rarely visible. Up to eight separate bows may be distinguished if the reflected and reflection rainbows happen to occur simultaneously: The normal (non-reflection) primary and secondary bows above the horizon (1, 2) with their reflected counterparts below it (3, 4), and the reflection primary and secondary bows above the horizon (5, 6) with their reflected counterparts below it (7, 8). Monochrome rainbow Main article: Monochrome rainbow
Unenhanced photo of a red (monochrome) rainbow
Occasionally a shower may happen at sunrise or sunset, where the shorter wavelengths like blue and green have been scattered and essentially removed from the spectrum. Further scattering may occur due to the rain, and the result can be the rare and dramatic monochrome or red rainbow. Higher-order rainbows In addition to the common primary and secondary rainbows, it is also possible for rainbows of higher orders to form. The order of a rainbow is determined by the number of light reflections inside the water droplets that create it: One reflection results in the first-order or primary rainbow; two reflections create the second-order or secondary rainbow. More internal reflections cause bows of higher orders—theoretically unto infinity. As more and more light is lost with each internal reflection, however, each subsequent bow becomes progressively dimmer and therefore increasingly harder to spot. An additional challenge in observing the third-order (or tertiary) and fourth-order (quaternary) rainbows is their location in the direction of the sun (about 40° and 45° from the sun, respectively), causing them to become drowned in its glare. For these reasons, naturally occurring rainbows of an order higher than 2 are rarely visible to the naked eye. Nevertheless, sightings of the third-order bow in nature have been reported, and in 2011 it was photographed definitively for the first time. Shortly after, the fourth-order rainbow was photographed as well, and in 2014 the first ever pictures of the fifth-order (or quinary) rainbow, located in between the primary and secondary bows, were published. In a laboratory setting, it is possible to create bows of much higher orders. Felix Billet (1808–1882) depicted angular positions up to the 19th-order rainbow, a pattern he called a "rose of rainbows". In the laboratory, it is possible to observe higher-order rainbows by using extremely bright and well collimated light produced by lasers. Up to the 200th-order rainbow was reported by Ng et al. in 1998 using a similar method but an argon ion laser beam. Tertiary and quaternary rainbows should not be confused with "triple" and "quadruple" rainbows—terms sometimes erroneously used to refer to the—much more common—supernumerary bows and reflection rainbows.
Rainbows under moonlight
Spray moonbow at the Lower Yosemite Fall
Main article: Moonbow Like most atmospheric optical phenomena, rainbows can be caused by light from the Sun, but also from the Moon. In case of the latter, the rainbow is referred to as a lunar rainbow or moonbow. They are much dimmer and rarer than solar rainbows, requiring the Moon to be near-full in order for them to be seen. For the same reason, moonbows are often perceived as white and may be thought of as monochrome. The full spectrum is present, however, but the human eye is not normally sensitive enough to see the colours. Long exposure photographs will sometimes show the colour in this type of rainbow. Fogbow
Fogbow and glory.
Main article: Fog bow Fogbows form in the same way as rainbows, but they are formed by much smaller cloud and fog droplets that diffract light extensively. They are almost white with faint reds on the outside and blues inside; often one or more broad supernumerary bands can be discerned inside the inner edge. The colours are dim because the bow in each colour is very broad and the colours overlap. Fogbows are commonly seen over water when air in contact with the cooler water is chilled, but they can be found anywhere if the fog is thin enough for the sun to shine through and the sun is fairly bright. They are very large—almost as big as a rainbow and much broader. They sometimes appear with a glory at the bow's centre. Fog bows should not be confused with ice halos, which are very common around the world and visible much more often than rainbows (of any order), yet are unrelated to rainbows. Circumhorizontal and circumzenithal arcs
A circumhorizontal arc (bottom), below a circumscribed halo
The circumzenithal and circumhorizontal arcs are two related optical phenomena similar in appearance to a rainbow, but unlike the latter, their origin lies in light refraction through hexagonal ice crystals rather than liquid water droplets. This means that they are not rainbows, but members of the large family of halos. Both arcs are brightly coloured ring segments centred on the zenith, but in different positions in the sky: The circumzenithal arc is notably curved and located high above the Sun (or Moon) with its convex side pointing downwards (creating the impression of an "upside down rainbow"); the circumhorizontal arc runs much closer to the horizon, is more straight and located at a significant distance below the Sun (or Moon). Both arcs have their red side pointing towards the sun and their violet part away from it, meaning the circumzenithal arc is red on the bottom, while the circumhorizontal arc is red on top. The circumhorizontal arc is sometimes referred to by the misnomer "fire rainbow". In order to view it, the Sun or Moon must be at least 58° above the horizon, making it a rare occurrence at higher latitudes. The circumzenithal arc, visible only at a solar or lunar elevation of less than 32°, is much more common, but often missed since it occurs almost directly overhead. Rainbows on Titan It has been suggested that rainbows might exist on Saturn's moon Titan, as it has a wet surface and humid clouds. The radius of a Titan rainbow would be about 49° instead of 42°, because the fluid in that cold environment is methane instead of water. Although visible rainbows may be rare due to Titan's hazy skies, infrared rainbows may be more common, but an observer would need infrared night vision goggles to see them. Rainbows with different materials
A first order rainbow from water (left) and a sugar solution (right).
Droplets (or spheres) composed of materials with different refractive indices than plain water produce rainbows with different radius angles. Since salt water has a higher refractive index, a sea spray bow doesn't perfectly align with the ordinary rainbow, if seen at the same spot. Tiny plastic or glass marbles may be used in road marking as a reflectors to enhance its visibility by drivers at night. Due to a much higher refractive index, rainbows observed on such marbles have a noticeably smaller radius. One can easily reproduce such phenomena by sprinkling liquids of different refractive indices in the air, as illustrated in the photo. The displacement of the rainbow due to different refractive indices can be pushed to a peculiar limit. For a material with a refractive index larger than 2, there is no angle fulfilling the requirements for the first order rainbow. For example, the index of refraction of diamond is about 2.4, so diamond spheres would produce rainbows starting from the second order, omitting the first order. In general, as the refractive index exceeds a number n+1, where n is a natural number, the critical incidence angle for n times internally reflected rays escapes the domain
[ 0 ,
displaystyle [0, frac pi 2 ]
. This results in a rainbow of the n-th order shrinking to the
antisolar point and vanishing.
The classical Greek scholar
René Descartes' sketch of how primary and secondary rainbows are formed
Descartes' 1637 treatise, Discourse on Method, further advanced this
explanation. Knowing that the size of raindrops did not appear to
affect the observed rainbow, he experimented with passing rays of
light through a large glass sphere filled with water. By measuring the
angles that the rays emerged, he concluded that the primary bow was
caused by a single internal reflection inside the raindrop and that a
secondary bow could be caused by two internal reflections. He
supported this conclusion with a derivation of the law of refraction
(subsequently to, but independently of, Snell) and correctly
calculated the angles for both bows. His explanation of the colours,
however, was based on a mechanical version of the traditional theory
that colours were produced by a modification of white light.
Round bottom flask rainbow demonstration experiment - Johnson 1882
Experiments on the rainbow phenomenon using artificial raindrops, i.e. water-filled spherical flasks, go back at least to Theodoric of Freiberg in the 14th century. Later, also Descartes studied the phenomenon using a Florence flask. A flask experiment known as Florence's rainbow is still often used today as an imposing and intuitively accessible demonstration experiment of the rainbow phenomenon. It consists in illuminating (with parallel white light) a water-filled spherical flask through a hole in a screen. A rainbow will then appear thrown back / projected on the screen, provided the screen is large enough. Due to the finite wall thickness and the macroscopic character of the artificial raindrop, several subtle differences exist as compared to the natural phenomenon, including slightly changed rainbow angles and a splitting of the rainbow orders. A very similar experiment consists in using a cylindrical glass vessel filled with water or a solid transparent cylinder and illuminated either parallel to the circular base (i.e. light rays remaining at a fixed height while they transit the cylinder) or under an angle to the base. Under these latter conditions the rainbow angles change relative to the natural phenomenon since the effective index of refraction of water changes (Bravais' index of refraction for inclined rays applies). Other experiments use small liquid drops, see text above. Culture Main article: Rainbows in culture
Depiction of the rainbow in the
Rainbows occur frequently in mythology, and have been used in the
arts. One of the earliest literary occurrences of a rainbow is in the
Book of Genesis
Eruption of Castle Geyser, Yellowstone National Park, with double rainbow
rainbow formed in kerala
Atmospheric optics Circumzenithal arc Circumhorizontal arc Iridescent colours in soap bubbles Sun dog
^ "Dr. Jeff Masters
Alexander of Aphrodisias, Commentary on
^ "Atmospheric Optics: Twinned rainbows". Atoptics.co.uk. 2002-06-03. Retrieved 2013-08-19. ^ See:
Alexander Haußmann, "Observation, analysis, and reconstruction of a twinned rainbow", Applied Optics [https://web.archive.org/web/20150216145150/http://www.opticsinfobase.org/ao/abstract.cfm?uri=ao-54-4-B117 Archived 2015-02-16 at the Wayback Machine. Vol. 54, Issue 4 (2015), pp. B117–B127] "Researchers unlock secret of the rare 'twinned rainbow,' " ScienceDaily.com, August 6, 2012. Archived August 9, 2012, at the Wayback Machine.
^ "Sadeghi et al. (2012) (computer simulations of rainbows)" (PDF).
Transactions on Graphics, 31(1): 3.1–3.12. Association for Computing
Machinery (ACM). Archived (PDF) from the original on 2016-01-27.
^ "Triple-split rainbow observed and photographed in Japan, August
2012". blog.meteoros.de. 2015-03-12. Archived from the original on
2015-04-02. Retrieved 2015-03-12.
^ "Can you ever see the whole circle of a rainbow? Earth". EarthSky.
2012-12-15. Archived from the original on 2013-10-04. Retrieved
^ Philip Laven (2012-08-04). "Circular rainbows". Philiplaven.com.
Archived from the original on 2013-10-05. Retrieved 2013-10-04.
^ "APOD: 2014 September 30 – A Full Circle
Thomas Young (1804) "Bakerian Lecture: Experiments and calculations relative to physical optics," Archived 2016-04-27 at the Wayback Machine. Philosophical Transactions of the Royal Society of London 94: 1–16; see especially pp. 8–11. Atmospheric Optics: Supernumerary Rainbows
^ Les Cowley (Atmospheric Optics). "Bows everywhere!". Retrieved 13
^ Nemiroff, R.; Bonnell, J., eds. (12 September 2007). "Six Rainbows
Across Norway". Astronomy Picture of the Day. NASA. Retrieved
^ "Atmospheric Optics: Reflection rainbows formation". Atoptics.co.uk.
Atmospheric Optics: Fogbow James C. McConnel (1890) "The theory of fog-bows," Archived 2013-12-04 at the Wayback Machine. Philosophical Magazine, series 5, 29 (181): 453–461.
^ Les Cowley. Observing Halos – Getting Started Atmospheric Optics,
accessed 3 December 2013.
^ "Circumzenithal Arc". www.atoptics.co.uk.
^ Cowley, Les. "Circumhorizontal arc". Atmospheric Optics. Retrieved
^ Science@NASA. "Rainbows on Titan". Archived from the original on
2008-09-21. Retrieved 2008-11-25.
^ Cowley, Les. "Sea Water Rainbow". Atmospheric Optics. Retrieved
^ Cowley, Les. "Glass Bead Bows". Atmospheric Optics. Retrieved
^ "The Internet Classics Archive –
Airy, G. B. (1838). "On the intensity of light in the neighbourhood of a caustic". Transactions of the Cambridge Philosophical Society. 6 (3): 379–403. Bibcode:1838TCaPS...6..379A. Archived from the original on 2013-12-05. G. B. Airy (1849) "Supplement to a paper, "On the intensity of light in the neighbourhood of a caustic," " Archived 2013-12-08 at the Wayback Machine. Transactions of the Cambridge Philosophical Society 8: 595–600.
^ G. Mie (1908) "Beiträge zur Optik trüber Medien, speziell
kolloidaler Metallösungen" Archived 2012-03-02 at the Wayback
Machine. (Contributions to the optics of turbid media, especially of
colloidal metal solutions), Annalen der Physik, 4th series, 25 (3):
^ Nussenzveig, H. Moyses (1977). "The Theory of the Rainbow".
Scientific American. 236 (4): 116. Bibcode:1977SciAm.236d.116N.
^ “Florence's Rainbow”, Harvard Natural Sciences Lecture
Demonstrations, link Archived 2017-01-08 at the Wayback Machine.
Greenler, Robert (1980). Rainbows, Halos, and Glories. Cambridge
University Press. ISBN 0-19-521833-7.
Lee, Raymond L. & Alastair B. Fraser (2001). The
Wikiquote has quotations related to: Rainbows
Wikimedia Commons has media related to Rainbow.
Interactive simulation of light refraction in a drop (java applet)
v t e
Red Orange Yellow Green Cyan Blue Indigo Violet Purple Magenta Pink Brown White Gray Black
Light Rainbow Visible
Spectral colors Chromophore
Structural coloration Animal coloration
On Vision and Colors Metamerism
Spectral power distribution
Monochromatic colors Complementary colors Analogous colors Achromatic colors (Neutral) Polychromatic colors
Impossible colors Light-on-dark Tinctures in heraldry
Blue Green Red Yellow Pink Purple Orange Black Gray White Brown
Blue–green distinction in language
List of colors: A–F
List of colors: G–M
List of colors: N–Z
List of colors
history pencil colors marker colors
Vision Image processing Multi-primary color display
Qualia Lighting Local color (visual art)
Category Portal Index of color-related articles