This produces a sheen of "white" light, making the inside of a rainbow much brighter than the outside. Visible light is only part of a rainbow. Infrared radiation exists just beyond visible red light, while ultraviolet is just beyond violet.
There are also radio wave s beyond infrared , x-ray s beyond ultraviolet , and gamma radiation beyond x-rays. Scientists use an instrument called a spectrometer to study these invisible parts of the rainbow. The atmosphere opposite a rainbow, facing the sun, is often glowing. This glow appears when rain or drizzle is falling between the viewer and the sun.
The glow is formed by light passing through raindrops, not reflected by them. Some scientists call this glow a zero-order glow. Sometimes, a viewer may see a "double rainbow. Double rainbows are caused by light being reflected twice inside the raindrop. As a result of this second reflection, the spectrum of the secondary rainbow is reversed: red is on the inner section of the arch, while violet is on the outside. Light can be reflected from many angles inside the raindrop.
A rainbow's "order" is its reflective number. Primary rainbows are first-order rainbows, while secondary rainbows are second-order rainbows.
Higher-order rainbows appear to viewers facing both toward and away from the sun. A tertiary rainbow, for example, appears to a viewer facing the sun. Tertiary rainbows are third-order rainbows—the third reflection of light. Their spectrum is the same as the primary rainbow. Tertiary rainbows are difficult to see for three main reasons. First, the viewer is looking toward the sun—the center of a tertiary rainbow is not the antisolar point, it's the sun itself.
Second, tertiary rainbows are much, much fainter than primary or secondary rainbows. Finally, tertiary rainbows are much, much broader than primary and secondary rainbows. Quaternary rainbows are fourth-order rainbows, and also appear to viewers facing the sun. They are even fainter and broader than tertiary rainbows. Beyond quaternary rainbows, higher-order rainbows are named by their reflective number, or order. In the lab, scientists have detected a th-order rainbow.
A twinned rainbow is two distinct rainbows produced from a single endpoint. Twinned rainbows are the result of light hitting an air mass with different sizes and shapes of water droplets—usually a raincloud with different sizes and shapes of raindrops. A supernumerary rainbow is a thin, pastel-colored arc usually appearing below the inner arch of a rainbow.
Supernumeraries are the result of the complex interaction of light rays in an air mass with small, similarly sized water droplets. In supernumerary formation, reflected rays interact in ways called constructive and destructive interference. Light is either reinforce d constructive interference or canceled out destructive interference.
Interference is responsible for the lighter hues and narrower bands of supernumeraries. A reflection rainbow appears above a body of water. A primary rainbow is reflected by the water, and the reflected light produces a reflection rainbow. Reflection rainbows do not mirror the primary rainbow—they often appear to stretch above it. A reflected rainbow appears directly on the surface of a body of water.
A reflected rainbow is created by rays of light reflected by the water surface, after the rays have have passed through water droplets. Reflected rainbows to not appear to form a circle with a primary rainbow, although their endpoints seem to meet in an almond-shaped formation.
Each water droplet acts like a tiny glass prism, bending the light that enters so that it exits at a different angle. Hence you can only see the reflected light if this angular difference matches the angle between you, the water droplet and the sun. The angle is fixed by the properties of air and water, so that you see a band of reflected light forming a semicircle with a radius of about 42 degrees.
The angle is slightly different for different colours of light, which is why the band appears coloured. Unfortunately, the fixed angle between you and each end of the rainbow means you can never reach one end to find that elusive pot of gold. David Roche, Helensburgh All rainbows start out straight. They become curved or bent under the weight of two pots of gold, one at each end of the rainbow.
As to why leprechauns hang them there, that is another big question. Ralph Gyoery, Chatswood Rainbows are formed by faraway drops of water reflecting and bending sunlight. The sunlight takes a complicated path through each water droplet. It comes in the side closest to the sun and then bends as it passes through the water droplet, bounces off the back surface of the droplet, travels back to the other side, and bends once again on its way out.
Only those water droplets that have the same angle formed by you, the drop, and the sun approx 42 degrees will contribute to the rainbow. The rainbow appears curved because the combined set of all these angles lies on a horizontal cone pointing at the sun with you at one tip. Now light from the sun is a mixture of different colours or wavelengths - red, yellow, green, blue, violet - that look white when they are superimposed.
The water droplet's density bends each colour's light path slightly differently which means the colours now appear split and visible.
This is what gives the rainbow its distinctive colour separation. David Buley, Seaforth Firstly, there is a lot more to a rainbow than meets the eye. Its longitudinal centre is located on the line between the sun behind you and the centre of your vision. To view the same rainbow a bystander would have look through the back of your head at eye level. Your rainbow is unique Now why are rainbows curved?
They are not only curved but are part of a circle. If you are high enough, say in an aeroplane, and the sun is low enough behind you, you will see a complete circle. We only see the upper section when at ground level. Particles of water occurring in a down-sun rainfall cause the suns rays to refract and they split into the familiar colour bands.
Remember the prism in junior school. Have enough of these particles occurring in sequence and the light paths scatter all over the place. You see the ones that are eventually directed back along your sight path.
Accepted light transmission physics embraces a concept of wave formation and particle photon travel. We select the most convenient one; wave pattern. The light receptor, in your case the human eye, is attuned to the amplitude of the wave. Now a specific point of amplitude locates a precise point along the wave length which is a measure of distance - in this case from to the rainbow to you.
So every part of your rainbow that you see is equidistant from you. Look through a leftover tube from your cling-film supply. The distance from your eye to the far edge is the same at all points and the far edge is circular. So is your rainbow. Tim Bowra, Rozelle. Why do dogs have wet noses? The wet nose helps cool dogs off, as they don't have sweat glands and can lose moisture only through the pads of their feet.
Jaya Seethamraju, Gladesville. Why are do dogs have wet noses: Why are human noses dry when cats, bears, weasels, shrews, koalas and most other animals have wet noses?
Elizabeth Latimer Hill, Denistone Well, the answer I like is because when Noah's Ark developed a leak, the hole was plugged by the nose of one of the dogs on board. That is why dogs' noses are always wet and cold! Mary Milton, Kenthurst. Guessing that sea salt comes from the sea, where does table salt come from?
Table salt is scooped off the top of the water table. Adrian Cooper, Queens Park. Table salt is found as rock deposits, then it is crushed and processed. Salt lakes are another source, where it is obtained through natural evaporation. During processing, iodine can be added, which helps to prevent cretinism, along with magnesium carbonate to make it free-running.
The locality of salt determines the colour; some is pink, for example, and is usually sold as more expensive gourmet salt. Some salts can be saltier than others and are used more sparingly, depending on taste.
Helen Triggs, Katoomba. The sea. To see the light coming back from the raindrops, look 42 degrees away from that antisolar point. Of course, the region of the sky 42 degrees away from that point is not just one direction but a whole collection of directions, one that forms a circle around the antisolar point.
Rainbows will always appear at that same angle from the antisolar point. The height of the rainbow, however, will depend on how high the sun is above the horizon. Each color of the spectrum gets refracted by a different amount when it passes from air to water or from water to air, the same as happens when light passes through a prism.
Consequently, the rainbow circle is not 42 degrees for all colors. The circle is smaller for blue rays than it is for red rays, so the primary rainbow is blue on the inside and red on the outside, with the intermediate colors of the spectrum spread out in between. If you look at a whole collection of such rays, you see a concentration of light coming back at an angle of 51 degrees. These rays produce a secondary rainbow, also centered on the antisolar point, having an angular radius of 51 degrees; the secondary rainbow therefore appears outside of the primary bow.
The sequence of colors is reversed in the secondary bow.
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