- 0.1 What is the real shape of the rainbow?
- 0.2 Are all rainbows arched?
- 0.3 Why is rainbow curved not straight?
- 0.4 Is it possible to touch a rainbow?
- 1 Is there an end to the rainbow?
- 2 Are rainbows actually full circles?
- 3 How long do rainbows last?
- 4 Why is called rainbow?
- 5 Is it rare to see the end of a rainbow?
- 6 Can planes fly through rainbows?
Why the shape of rainbow is curved?
Hint- Rainbow is formed due to refraction of rays in water droplets A ray of light entering a spherical water droplet will undergo refraction twice and the ray which is coming out of the droplet will be dispersed into the seven component colors of white light.
- Complete step-by-step answer: Rainbow is formed due to refraction of rays in water droplets.
- A ray of light entering a spherical water droplet will undergo refraction twice and the ray which is coming out of the droplet will be dispersed into the seven component colors of white light.
- The water droplets act like a prism.
The rainbow that is formed is actually a full circle but we are able to see only an arc because the horizon cuts off the lower half so we are not able to see the full circle. if we are high enough then we would be able to see the complete circle of rainbow.
- The reason why rainbows appear to be curved is because of the angle at which the raindrops reflect the light.
- Usually the angle at which the sunlight is reflected from a droplet is about 42 degrees.
- So, we can say that it is actually due to the spherical shape of the raindrops that the rainbows have a circular shape.
Note: The rainbow that is formed is actually a full circle but we are able to see only an arc because the horizon cuts off the lower half. The reason for the circular shape is the spherical shape of the droplets which reflect light at an angle making a cone of light.
What is the real shape of the rainbow?
A rainbow is a multicolored arc made by light striking water droplets. The most familiar type rainbow is produced when sunlight strikes raindrops in front of a viewer at a precise angle (42 degrees). Rainbows can also be viewed around fog, sea spray, or waterfalls,
A rainbow is an optical illusion —it does not actually exist in a specific spot in the sky. The appearance of a rainbow depends on where you’re standing and where the sun (or other source of light) is shining. The sun or other source of light is usually behind the person seeing the rainbow. In fact, the center of a primary rainbow is the antisolar point, the imaginary point exactly opposite the sun.
Rainbows are the result of the refraction and reflection of light. Both refraction and reflection are phenomena that involve a change in a wave ‘s direction. A refracted wave may appear “bent,” while a reflected wave might seem to “bounce back” from a surface or other wavefront.
- Light entering a water droplet is refracted.
- It is then reflected by the back of the droplet.
- As this reflected light leaves the droplet, it is refracted again, at multiple angles.
- The radius of a rainbow is determined by the water droplets’ refractive index,
- A refractive index is the measure of how much a ray of light refracts (bends) as it passes from one medium to another—from air to water, for example.
A droplet with a high refractive index will help produce a rainbow with a smaller radius. Saltwater has a higher refractive index than freshwater, for instance, so rainbows formed by sea spray will be smaller than rainbows formed by rain. Rainbows are actually full circles.
- The antisolar point is the center of the circle.
- Viewers in aircraft can sometimes see these circular rainbows.
- Viewers on the ground can only see the light reflected by raindrops above the horizon,
- Because each person’s horizon is a little different, no one actually sees a full rainbow from the ground.
In fact, no one sees the same rainbow—each person has a different antisolar point, each person has a different horizon. Someone who appears below or near the “end” of a rainbow to one viewer will see another rainbow, extending from his or her own horizon.
- Colors A rainbow shows up as a spectrum of light: a band of familiar colors that include red, orange, yellow, green, blue, and violet.
- The name ” Roy G.
- Biv ” is an easy way to remember the colors of the rainbow, and the order in which they appear: red, orange, yellow, green, blue, indigo, and violet.
(Many scientists, however, think “indigo” is too close to blue to be truly distinguishable,) White light is how our eyes perceive all the colors of the rainbow mixed together. Sunlight appears white. When sunlight hits a rain droplet, some of the light is reflected.
- The electromagnetic spectrum is made of light with many different wavelengths, and each is reflected at a different angle.
- Thus, spectrum is separated, producing a rainbow.
- Red has the longest wavelength of visible light, about 650 nanometers,
- It usually appears on the outer part of a rainbow’s arch.
Violet has the shortest wavelength (about 400 nanometers) and it usually appears on the inner arch of the rainbow. At their edges, the colors of a rainbow actually overlap. 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 waves (beyond infrared), x-rays (beyond ultraviolet), and gamma radiation (beyond x-rays).
- Scientists use an instrument called a spectrometer to study these invisible parts of the rainbow.
Rainbow Variations Glow 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. Double Rainbow Sometimes, a viewer may see a “double rainbow.” In this phenomenon, a faint, secondary rainbow appears above the primary one. 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.
Higher-Order Rainbows 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 200th-order rainbow.
- Twinned 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. Supernumerary Rainbow 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 reinforced ( constructive interference ) or canceled out (destructive interference).
Interference is responsible for the lighter hues and narrower bands of supernumeraries. Reflection Rainbow 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. Reflected Rainbow 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. Red Rainbow A red rainbow, also called a monochrome rainbow, usually appears at sunrise or sunset. During this time, sunlight travels further in the atmosphere, and shorter wavelengths (blue and violet) have been scattered.
- Only the long-wavelength red colors are visible in this rainbow.
- Fogbow A fogbow is formed in much the same way as a primary rainbow.
- Light in a fogbow is refracted and reflected by fog (water droplets suspended in air).
- A fogbow seen in the clouds is called a cloudbow.
- Because the water droplets in fog are much smaller than raindrops, fogbows have much fainter colors than rainbows.
In fact, some fogbows have few detectable colors at all and appear mostly white, with a reddish tinge on their outer edge and a bluish tinge on their inner edge. Moonbow A moonbow, also called a lunar rainbow, is a rainbow produced by light reflected by the moon.
- The moon itself does not emit light, of course.
- Moonlight is reflected sunlight, as well as some starlight and ” Earthlight,” Because moonlight is so much fainter than sunlight, moonbows are dimmer than rainbows.
- Rainbows in Myth Rainbows are part of the myths of many cultures around the world.
- Rainbows are often portrayed as bridges between people and supernatural beings.
In Norse mythology, for instance, a rainbow called the Bifrost connects Earth with Asgard, where the gods live. In the ancient beliefs of Japan and Gabon, rainbows were the bridges that human ancestors took to descend to the planet. The shape of a rainbow also resembles the bow of an archer,
Hindu culture teaches that the god Indra uses his rainbow bow to shoot arrows of lightning, Rainbows are usually positive symbols in myths and legends. In the Epic of Gilgamesh and, later, the Christian Bible, the rainbow is a symbol from a deity (the goddess Ishtar and the Hebrew God) to never again destroy Earth with floods.
Sometimes, however, rainbows are negative symbols. In parts of Burma, for instance, rainbows are considered demons that threaten children. Tribes throughout the Amazon Basin associate rainbows with disease. Perhaps the most famous piece of mythology surrounding rainbows is the Irish legend of the pot of gold at the end of a rainbow.
- The gold is guarded by a tricky leprechaun, but—because no one sees the same rainbow and rainbows don’t “end” (they’re circles)—no one ever finds the gold or the magical creature.
- Rainbow Flags Rainbow flags usually appear as stripes (bands) of at least five different colors.
- Rainbow flags have long represented groups championing diversity, respect, and inclusiveness,
The Wiphala is a type of rainbow flag. It is a symbol of communities indigenous to the Andes, stretching from modern-day Ecuador to Chile. A Wiphala has been an official flag of Bolivia since 2009, when the nation elected its first indigenous president, Evo Morales.
The Wiphala features a diagonal patchwork design with squares in different rainbow colors. Different arrangements of patchwork squares represent different Andean communities. The Buddhist flag, designed in the 19th century, is flown by Buddhists around the world. It is a vertical arrangement of six bands, each representing a different aspect of Buddhism, from kindness to moderation, blessings to wisdom.
The Jewish Autonomous Oblast, a community on Russia’s border with China, is represented by a seven-banded rainbow flag. The seven bands symbolize the seven branches of a menorah, The most familiar rainbow flag may be the banner representing the movement supporting civil rights for members of the lesbian, gay, bisexual, and transgender ( LGBT ) community.
- The different colors of the “LGBT pride” flag represent the diverse community itself, as well as different aspects associated with each color.
- Orange, for example, symbolizes health and healing, while green symbolizes nature.
- Fast Fact Rainbows Near and Far Some scientists think rainbows also exist on Titan, one of the moons of the planet Saturn.
Titan has a wet surface and humid clouds. The sun is also visible from Titan, so it has all the ingredients for rainbows.
Are all rainbows arched?
Seeing a rainbow can feel like a reward. After a violent thunderstorm, it’s nice to spot a colorful arch crossing the calming sky. But you might (or might not) be surprised to know that rainbows aren’t really arches, nor are they ‘bows.’ They’re actually full circles.
Why is rainbow curved not straight?
This was published 17 years ago December 31, 2005 — 11.00am Why are rainbows curved? Because of the heavy pots of gold at each end. Grahame Marr, Kingscliff Like a few shady characters around, they’d be less colourful if they went straight. Randolph Magri-Overend, Point Clare If they were straight, the gay community wouldn’t have a symbol.
Rich Cuskelly, Carlingford A rainbow is the diffraction of sunlight through water droplets in the air. To see a rainbow, you need to be looking at light rain with the sun behind you. The rainbow is curved as it reflects the round shape of the sun. It is a semicircle because only half of your field of vision is the air (the other half is the Earth).
If you are in an aeroplane with the sun directly overhead and you look down into a raincloud, you will see the rainbow is a full circle, again reflecting the fact the sun is round. John Frith, Paddington Rainbows are circular because raindrops are spherical.
When light from the Sun enters a raindrop it is largely reflected back inside a cone with a half-angle of 42 degrees. The reflected light is strongest along the surface of this cone where it is broken up into a spectrum of colours. When we see a rainbow we are looking at those drops from which the light along the surface of the cone enters our eyes.
Consequently, a line from the Sun through our head passes through the centre of the circular rainbow. The angle between this line and any point on the rainbow is about 42 degrees. (A bit complicated? Following the explanation with a paper cone in your hand might help!).
- Colin Gauld, Kiama Downs Because they are weighed down by the pots of gold at the ends.J.
- Barrie Brown, Gordon Because if they were straight you would never be able to get the pot of gold at the end.
- Sam Duddy, Wollongong We see the shape of a rainbow as a curve because we are looking at it from a globe, and the light adjusts to the shape of the planet.
Alice Russo, Paddington A rainbow is formed when sunlight is reflected from droplets of water in the atmosphere back towards you. 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, it’s yours! 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.
Ie: The brighter the light, the greater the amplitude; just like radio transmission. 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? Sam Duddy, Wollongong Now doggies have their noses wet,/I’ll tell you this tale as a friend./The reason that their noses are wet/Is the wiper’s at the wrong end! Sandy Parkinson, Hilton, WA So they don’t burn other dogs’ bottoms! 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. Michael Morton-Evans, Mosman The Dutch Salt industry of the 15 to 16th century developed to such a degree that it and the herring trade became the backbone of the Dutch economy.
The sea salt and salt from springs that they used were so contaminated by impurities that the salt was often highly corrosive. With the introduction of highly purified salt, it could be presented upon the table in salt cellars of great beauty, we recall Cellini’s name in this regard. In brief then, a salt on the table was highly purified and non-corrosive.
Dr Con Scott Reed, Mosman Either the supermarket, or the pantry. Steve Barrett, Glenbrook Maybe from where I live: the tablelands. Bob Dengate, Bathurst How does insect spray kill insects? Most contain substances – such as oils – that physically block and/or cause damage to the insect’s airways.
Insects breathe through small perforations along their body, which are more easily blocked than a nose or mouth. Insecticides also generally contain additional substances, such as pyrethrins and cholesterinase inhibitors, which interfere with the insect’s nervous system. Other poisons may induce catastrophic changes to the insect’s chemical balance, for example, by displacing potassium or calcium from body fluids.
Peter R. Green, Marrickville Most insect sprays contain neurotoxins (poisons which act on nerve cells) called pyrethrins, which come from the seeds of the pyrethrum plant. Spraying an insect with a pyrethrin will ususally cause paralysis, as the nerve cells stop working, which will immobilise and then kill the insect.
Although deadly to insects (and fish), pyrethrins are fairly non-toxic to mammals and birds because their bodies can transform them into harmless substances. However, human contact with pyrethrins can trigger skin allergies or cause breathing difficulty if inhaled (pyrethroids, made from chemicals rather than pyrethrum seeds, are less allergenic).
Also, industrial insecticides, such as those used in commerical pest control, are often extremely toxic to humans, so should be treated with more caution. Greg Turner, Surry Hills Insecticides work by stopping the reabsorbtion of the chemical which allows contact between neurons in the insect’s brain.
The neurons cannot stop firing, thus we see the uncontrollably twitching limbs of a poisoned insect. In effect their brains are burnt out. These chemicals are known as anti-colinesterase agents. DDT had the same effect and in the 1950s small amounts were sometimes added to cocktails to give an added `buzz’.
Dave Standfield, Kandos Many of the current insect sprays destroy the wax coating of the insect’s respiratory system. When applied directly, the insect suffocates and die instantly. Jaya Seethamraju, Gladesville They don’t. The sprays are formulated to trigger a self-destruction response, which causes the insects to hang themselves.
- That’s why the stuff is called `insecticide’.
- Matt Petersen, Randwick All contain poisons that interfere with the nervous system in varying ways, usually by prolonging or shutting down the activity of neurotransmitters.
- Pyrethroids, alkaloids, nicotine and rotenone, based on the natural insecticides found in chrysanthemum, sabadilla, tobacco and derris root plants, all kill insects in this way.
Paul Roberts, Lake Cathie When does ancient history stop and become modern history? It’s not that simple. Ancient history runs from when Adam and Eve were kids until the demise of the Western Roman Empire in AD476. The world then slipped into the Dark Ages, until about AD1000 or until the beginning of the European Renaissance in the 14th century, depending on which historical authority you side with.
- Modern history starts with the Renaissance, or in 1789 – again depending on which historical authority you side with.
- Jim Dewar, North Gosford According to my daughter, ancient history is everything that happened before she was born.
- Peter Ryall, Lake Haven When the school bell rings between those two lessons.
Kevin Ford, Little Bay It doesn’t – at least not in Europe, which is the only place where these historical divisions really mean anything. Medieval History, roughly AD 500 to 1500, comes in between. Norm Neill, Leichhardt Yesterday. Michael Morton-Evans, Mosman If we understand that history will continue for the rest of the century, and the rest of the life of the universe, and that in a million years this period will not be labelled Modern History, we can understand that historians decide the placement of names of certain periods to the ease of their present understanding, as in, we don’t call 300 BC Modern History, because life and the recordance of that living has continued.
Ancient History ended approximately after the fall of the Roman Empire. The Middle Ages followed, then Modern History occurred in the late nineteenth century to the early twentieth, and still continus today. Ignatius J Wilson, Queenscliff From memory, Ancient History ends with the fall of the Western Roman Empire, with Modern History beginning with the French Revolution.
The period between is usually called `The Middle Ages’ or `The Medieval Age’. Cameron Mason, Lapstone There seems to be a gap between when Ancient History stops and when Modern History starts. According to the Department of Education NSW, Ancient History stops around AD 300, when Alexander and the Romans had conquered everything.
Modern history starts around the late 19th century, when some of the major wars began. I unfortunately found this out when picking subjects for the HSC. I had wanted to study the middle bit, which included the Dark Ages, Middle Ages, the Renaissance and the Reformation. So where do these periods of history fit in? Rachael Diacono, Collaroy Plateau On my 21st birthday.
Sandy Parkinson, Hilton, WA Ancient history specifically refers to times prior to the fall of the western Roman empire in 476 AD. Darryl Buley, Cherrybrook Every high school history student, ancient or modern, knows Ancient History stops and Modern History begins at The French Revolution.
Mark Harris, Randwick Modern History does not immediately take over from Ancient History. The two are separated by about 1200 years of historical periods known variously as The Dark Ages, the Medieval period, the Renaissance, etc. In summary, Ancient History is circa 4000 BC to circa AD 500, Dark Ages, Medieval, Renaissance, etc 500 to 1789, Modern History, 1789 to the present.
Andrew Lundy, Cheltenham, UK On our school’s timetable, after recess. Denis Kirkaldy, Carlingford It doesn’t. On the contrary, Modern History becomes Ancient History as soon as you stop and look back at it. Kay Thiel, Collaroy At the end of term 2. Phil Butterss, Parkside, SA How is it we’ve managed to pinpoint December 25 as Christ’s birthday and yet the day of His crucifixion varies according to lunar cycles? The questioner suggests that we have pinpointed December 25 as Jesus’ birthday; Bill Phippen says that the date is completely unknown.
- The truth lies somewhere between these two extremes.
- The year of His birth was most likely 4 BC.
- References in Luke’s gospel to Caesar Augustus and the Governor of Syria, Quirinius, and in Matthew’s gospel to King Herod, help determine the year.
- The month was possibly April or May, as shepherds came from the fields to see the baby, but it would have been too cold before then for overnight open air shepherding.
This was also a time when many sheep were herded in the Bethlehem area in preparation for the Passover sacrifices and meal. (Rev) Peter R Green, Marrickville Members of the Danish royal family wear the blue sash of the Order of the Elephant on formal occasions.
- Elephants are not native to Denmark, so what is the connection? The Order of the Elephant is the oldest and most distinguished order and dates back to the 15th century.
- The statutes of the Order were established by Christian V on 1 December 1693.
- In earlier times the Order was mainly conferred on foreign princes and distinguished Danish noblemen.
Nowadays the Order is almost exclusively awarded to Heads of State and Members of the Royal Family. The explanation for the elephant as the symbol of the Order is most likely that a warrior elephant was used as a symbol for the defenders of Christianity who were incensed at the sight of Christ’s blood.
At the same time the elephant symbolised purity and chastity. Roy MacPherson, New Zealand Big Questions is edited by Harriet Veitch ANY ANSWERS? * Does a fly do a loop or a barrel roll to get into position to land upside down on the ceiling? * Who taste-tests pet food? * Why do clouds clump together and not spread out? * Are there any days or weeks in the year not yet appropriated by some awareness cause or other? * Considering the laws of buoyancy, the increasing pressure below sea level, and the density of steel, why don’t steel shipwrecks float at about 70 metres below sea level? READERS’ RESPONSES By Tuesday at noon, email your answers – or questions – to [email protected]; write to Big Questions, Spectrum, SMH, GPO Box 506, Sydney 2001; or send a fax to 9282 2481.
Limit questions to one short sentence and answers to a maximum of 130 words, and state your name and suburb/town.
Is it possible to touch a rainbow?
Rainbow is formed just because of dispersion of white light due to raindrops. Technically different colours are light waves of different wavelengths. Since we can not touch light, so we can not even touch a rainbow.
Is there an end to the rainbow?
As a rainbow is simply a form of optical illusion, as you move around where light is reflected by the rain the view also changes. No matter how, or where, you move the rainbow will always move further away making that pot of gold forever unattainable.
Are rainbows actually full circles?
Think about the last time you saw a rainbow; what was it like? It was probably evidently a “bow,” for starters, where it made its classic arc-like shape, with colors changing from red on the outside through the full spectrum of colors, down to blue/violet on the interior.
- There may have been a secondary rainbow, fainter and with color-order reversed, above it.
- The weather conditions were probably a mix of cloudy, rainy skies and cloud-free, sunlit streaks, or otherwise it was likely sunny and you had a lot of mist nearby.
- And although you probably don’t think of it as being a remarkable occurrence, it was probably daytime and you were probably somewhere on the surface of the Earth.
What you might not realize is that the shape of a rainbow isn’t a “bow” or an “arc” at all, but rather a full circle. The only reason you see part of that full circle, under most conditions, is because the Earth itself (or other foreground features) are in the way, preventing you from seeing the entire rainbow at once.
- But there are certain tricks you can use to overcome those terrestrial limits, enabling you to see the full-circle rainbow all at once.
- These range from flying in an airplane with the Sun on one side and copious rainfall/clouds on the other to simply orienting yourself with your back to the Sun while spraying the fine mist from a garden hose.
Here’s the science of how rainbows work, and why they truly are full circles. When white light, or sunlight, strikes a spherical drop of water, that light will enter-and-leave the drop at a specific set of angles, with light of differing wavelengths leaving at slightly different angles. The result, whether the drops are created by rain, mist, waterfall spray, or sprinkler/garden hose, is always a rainbow with the exact same set of angles and optical properties.
- a source of white light,
- drops of water to reflect that light,
- and an observer with the right geometric perspective to see it.
Rainbows aren’t physically “real objects,” in the sense that if you move toward or away from one, the rainbow will shift in response to your motion. Each observer at each unique location sees their own individual rainbow. It’s why any attempt to find the proverbial “pot of gold at the end of the rainbow” will always fail, as rainbows don’t have a beginning or end; they’re a purely optical phenomenon, only appearing at a specific set of angles relative to the Sun and the specific location of the person or camera viewing them. Through the vacuum of space, all light, regardless of wavelength or energy, travels at the same speed: the speed of light in a vacuum. When we observe light from a distant star, we are observing light that has already completed that journey from the source to the observer.
- Credit : Lucas Vieira/Wikimedia Commons Think about what happens when you pass a beam of white light through a prism.
- Before that light enters the prism, all the different wavelengths — or colors of light — are propagating together.
- That’s why the light appears white: because it’s all the different wavelengths and colors all together.
Each photon that makes up the white light has two properties: wavelength and frequency, where the wavelength is the distance between two successive “peaks” or “troughs” of light (i.e., the electromagnetic wave) and frequency is how many wavelengths-of-light are contained in each second of travel for the electromagnetic wave.
- In the vacuum of empty space, the wavelength of light multiplied by the frequency of light always equals exactly the same value: the speed of light.
- But when that light passes through a medium, it slows down.
- Through something like air, it only slows down by 0.03% or so, a completely negligible value.
But through acrylic, it slows down by 33%; through zircon, it slows by 48%; through diamond, it slows by 59%. It also moves slower through water, slowing down by about 25% from its vacuum speed. And while the frequency of the light never changes, even as it moves through a medium, both its wavelength and its speed do. When white light strikes a spherical drop of water, the light refracts at the interface, bending at a particular angle that has a very slight wavelength dependence, with shorter-wavelength (violet) light bending slightly more than longer wavelength (redder) light.
The light then reflects off of the back of the water drop, and then exits the water drop at the next interface, releasing the light of different wavelengths (and colors) at slightly different angles from one another. Credit : KES47 & Algocu/Wikimedia Commons Think about that for a second. The frequency of light cannot change, because if it did, it would violate the conservation of energy; the energy of a photon is just a constant (Planck’s constant) multiplied by the frequency, so if we want energy to be conserved (and physics mandates that), then the frequency cannot change.
But the wavelength can change, and therefore so must the speed of each individual photon, or quantum of light. But by how much? You might think it’s by the same exact amount, as I did just tell you earlier that light slows down by:
- 0.03% through air,
- 25% through water,
- 33% through acrylic,
- 48% through zircon, and
- 59% through diamond.
That’s true, but only on average. As it turns out, each individual medium slows light down by a slightly different amount, dependent on both wavelength and temperature. In general, “bluer” (or shorter-wavelength) light slows down by a little bit more than “redder” (or longer-wavelength) light, and hotter temperatures for your medium cause light to slow down by a little bit more than it does in a colder medium. The behavior of a beam of sunlight, perhaps the greatest example of white light, as it passes through a prism demonstrates how light of different energies moves at different speeds through a medium, but how they all move at the same speed through a vacuum, which is why the light that doesn’t pass through a refractive medium remains white in color.
Credit : Kelvinsong/Wikimedia Commons It’s this physical effect that leads to the optical phenomenon of a rainbow. When sunlight, an example of white light, strikes a water drop, some of that light will actually enter the water for a time, slowing down, only to exit the water drop and have the light return back to normal speed.
But the time it spent in that water drop causes the colors to separate, which is why you can shine sunlight through water and see color separation i.e., a rainbow effect when the light returns back into the air. For the type of rainbow that you see when sunlight strikes rain, you have to remember two facts:
- that all of the Sun’s rays are parallel,
- and that water drops are roughly spherical.
The rest is just geometry. When white light strikes a water drop at just the right angle, it won’t reflect off of the drop completely, but some of the light will refract, entering the drop and “splitting” the various wavelengths apart. When the light makes it to the back of the drop, it can reflect off of the back of the drop, causing the light to head back toward the Sun.
But this time, when the light hits the water/air surface again, it moves from the water back into the air. What’s remarkable is that because the geometry, the light, and the water are always the same, the light always makes the exact same set of angles: 42° for red light, 40° for violet light, with the full spectrum of colors between them.
This was known nearly 400 years ago, and was illustrated in 1637 by René Descartes, As first illustrated by René Descartes in 1637, an observer facing away from the Sun will see a primary rainbow due to light taking the path from (A), where it collides with a water drop (B), reflects off of the back of the drop (C), exits the drop (D) and goes toward the observer’s eyes.
A secondary rainbow instead takes a path (starting at F) where it hits the water drop (G), reflects twice off of the drop’s interior (H and I), and then exits the drop (K) to make a secondary rainbow. Both of these rainbows are true full-circles, as the inset illustration, with modern names and a color-coded diagram, illustrates, Credit : René Descartes (main), CMG Lee/Wikimedia Commons (inset) Think about what this means: the sunlight strikes the water, enters it, reflects once off of the back of the drop, and exits the drop.
Red light always exits at a 42° angle; violet light always exits at a 40° angle, and the other colors fill in the spaces in between: in classic ROY-G-BIV order. With your back to the Sun, wherever those drops of water exist to form a rainbow, the shape and color of the rainbow will always be the same: at the exact same set of geometric angles, wherever these spherical drops of water exist to reflect the light.
- In some cases, you won’t have intervening drops of water; these will appear as “gaps” in the rainbow.
- In some cases, when the Sun is quite high above the horizon, you can only see a tiny fraction of the arc close to the horizon; to the contrary, when the Sun is very low in the sky, you can see a full, large semicircle of a rainbow spanning an enormous swath of the sky.
(In fact, if the Sun is more than 42° above the horizon, you won’t see a rainbow at all, because the geometry of the Sun-raindrop-observer system is all wrong.) As a result, the most spectacular rainbows often appear very close to sunset, when large parts of the western horizon, where the Sun is setting, are clear, but where it’s raining over toward the east, where the Sun’s rays will reflect off of the drops. When the Sun is high in the sky, but less than 42 degrees above the horizon, the arc of a primary rainbow can be seen in the rain or mist, as here, but will appear very low on the horizon. As the Sun sets lower and lower, any rainbows that appear will rise higher and higher in the sky.
- However, with the surface of the Earth in the way, only half of the true, full circle rainbow can be seen.
- Credit : DeFacto/Wikimedia Commons If you’re on the surface of Earth, however, it’s usually impossible to see the true optical shape of a rainbow: a full circle, because there are only spherical drops of water in the atmosphere above the Earth’s surface, not down beneath the Earth’s surface, for the sunlight to reflect off of.
If you rise up above the surface of the Earth, however, such as in a hot air balloon, a blimp, or an airplane, however, this suddenly becomes possible as long as the Sun cooperates. If you look in the opposite direction of the Sun, while airborne, there’s a “band” corresponding to the angles that are offset between 40° and 42° degrees from the imaginary line connecting the Sun to your eyes and beyond, to the horizon (or into the ground) in the opposite direction. This circular rainbow was captured while skydiving, as the sunlight reflected off of sources of misty water, below. The ubiquitous bright sunlight and lack of clouds (save the small shadowy one seen in the photograph) suggest that it’s the mist of irrigation sprays that are causing much of the rainbow effect at the bottom of the frame, while clouds/water droplets create the primary and secondary rainbows seen atop the image.
- Stand with your back to the Sun.
- Point the garden hose so that it’s pointing at the shadow of your head on the ground.
- Open the hose so that the spray is wide and misty, and so that the spray particles extend for more than 42° away from your line-of-sight in all directions.
- Look at what happens.
- See the full-circle rainbow.
That’s it! With a little more sophistication, you can even construct a “sheet of rain” by having a large set of misting sprinklers set up with the right configuration to reflect the sunlight into the eye of the observer or camera lens. When the Sun’s rays reflect off of the droplets between 40° and 42° relative to the Sun-observer line and all get focused back into the observer’s field of vision all at once, a fully circular rainbow arises as a consequence of the science of optics. Through a clever setup involving misting sprinklers and by waiting for the Sun to be low enough in the sky to create the desired optical effects, a full-circle rainbow can be seen from the ground. The rainbow’s interior radius is always 40 degrees; its exterior radius is always 42 degrees. Travel the Universe with astrophysicist Ethan Siegel. Subscribers will get the newsletter every Saturday. All aboard! As a result, a fainter, color-order-reversed rainbow appears at a wider angle than the original rainbow: between 53.5° for the outer, violet layer and 50.4° for the inner, red layer, with the reversed-from-typical colors ordered VIB-G-YOR from the outside in. As photographed from an airplane, direct sunlight shining on a “wall of water droplets” produced by rain clouds can not only produce a full-circle primary rainbow, but a full-circle secondary as well, creating a circular double rainbow. Credit : oskarslidums/reddit, imgur It’s remarkable to realize that because rainbows aren’t physically real — they’re just optical phenomena, like shadows — that if you could simply add more “mist particles” for the sunlight to reflect off of in the right locations, you’d be able to see the true shape of a rainbow every time: a full circle, with an inner (violet) angular radius of 40° and an outer (red) angular radius of 42°.
- Similarly, a color-reversed, fainter secondary full-circle rainbow always exists as well, with an inner (red) angular radius of 50.4° and an outer (violet) radius of 53.5°.
- Wherever you can recreate these conditions, you’ll be able to see the full rainbows in all their glory.
- In fact, fainter and fainter rainbows exist, with a new set of angles determined solely by geometry, with each new internal reflection that you add.
The tertiary (three-reflection) and quaternary (four-reflection) rainbows are in the sunward direction, so human eyes are terrible at seeing them, but the quinary (five-reflection) rainbow actually falls in between the primary and secondary rainbow, and was photographed for the first time by humans back in 2014.
What is at the end of a rainbow real?
Answer – Disappointing news for Billy – the rainbow doesn’t touch the ground and there is no end to it. Light from the sun looks white, but it is actually made of lots of different colours. Normally, they are all mixed together. A rainbow is formed when light from the sun meets raindrops in the air and the raindrops separate out all these different colours.
Because rainbows are made in the sky, they don’t touch the ground. So if you’re on the ground, however far you walk, the end of the rainbow will always look as if it were on the edge of the horizon. But what people don’t realise is that rainbows are actually complete circles, and obviously a circle has no end.
You never see the whole circle because the earth’s horizon gets in the way. Apparently, if you see a rainbow from a plane it should be almost a complete circle. Another interesting fact about rainbows – have you ever noticed that you’ll only ever see a rainbow if the sun is behind you? You can also sometimes see miniature rainbows in your garden if you’re watering your plants with the sun behind you.
How long do rainbows last?
How do rainbows form? – A primary rainbow is formed when light shines through water droplets. It happens most often when the sun shines through the rain. This white light bends and reflects, causing all of the beautiful different colors to appear.
Why are rainbows double?
How are double rainbows formed? – Double rainbows are formed when sunlight is reflected twice within a raindrop with the violet light that reaches the observer’s eye coming from the higher raindrops and the red light from lower raindrops. This means the sequence of colours is inverted compared to the primary rainbow, with the secondary bow appearing about 10 degrees above the primary bow.
Can rainbows form on moon?
No, rainbow is formed when light gets reflected back from inside of water drops since there is no atmosphere on the moon this can’t happen.
Do rainbows touch the ground?
The Science of Rainbows Everyone has imagined the pot of gold at the end of the rainbow and seen that moment at the end of a rainstorm. But rainbows are much cooler and much more complicated than you might think. Rainbows are actually the result of the reflection and refraction of light. Refraction and reflection both occur in rainbows and both involve a change in the direction of a light wave. Refraction of light tends to “bend” the light off of its original trajectory, this can bend the light to different angles, including a complete right angle bend. This tends to occur when the light wave hits a substance with a different viscosity than air. For example, glass or water. Reflection is when the light is “bounced” back from a surface or wavefront, for example, light bouncing back in a raindrop. Each colour of light has a different wavelength and therefore refracts a slightly different amount of light. Because of this, when the light hits the raindrop, the refraction separates the colours and sends them out of the raindrop in different directions.
This creates a rainbow in the sky as the different colours are reflected at different angles. However, every now and then, only certain colours will make it through the raindrop and the leftover light will reflect off the edges of the raindrop. When this light hits the other side, it has already been separated into colours and is reversed as it is a reflection.
This is what causes a double rainbow to appear as an exact, if not fainter, mirror image of the primary rainbow. At the end of the rainbow, you’ll find a pot of gold! Everyone knows that the pot of gold is a myth, but did you know that so is the end of the rainbow? Rainbows never actually touch the ground! They look like they do due to a prism-ing effect but if you go high enough, in a plane or on a mountaintop, and look down on a rainbow; it will be completely circular! And did you know rainbows can literally go full circle? It’s true. Did you know that white light is composed of all colours? This includes red, orange, yellow, blue, green, violet, and indigo along with ultraviolet and infrared colours! When the white light refracts and reflects through the raindrops, the light is divided into all visible colours to create a rainbow.
- Each colour has a unique wavelength, going from red with the greatest wavelength to violet with the smallest wavelength.
- It is this wavelength that determines whether a colour will go through the rainbow or be refracted back.
- The colours in the rainbow are also affected by the time of day when you are seeing them.
The best time for a rainbow to be seen is the early morning or afternoon after a rainstorm. In these conditions, there is a large amount of water vapour in the atmosphere and low light levels. On the other hand, if it is the middle of the day, you are unlikely to see a rainbow as most water vapour has likely evaporated and it is much harder to hit the correct angle for a rainbow.
- During the middle of the day, you will likely only see small rainbows.
- During sunrise and sunset, you are likely to see a red rainbow rather than a multi-coloured rainbow you would normally expect.
- This is because during these times of day the light has to travel further in the atmosphere and often the shorter wavelengths, like violet and blue, have already been scattered.
This means that only the longer-wavelength colours like red and orange are visible, creating a monochromatic rainbow. Want to learn more about light refraction and reflection and the science of light? Book in for Street Science’s Year 5, With over a decade of experience in science education and with all of our staff having science and education backgrounds, our workshops are fun and educational and range from kindy all the way to senior school. or to learn more. : The Science of Rainbows
Why don t rainbows move?
Why can’t we reach the end of a rainbow? Asked by: Tom Roberts, Liverpool A rainbow isn’t a fixed object that hangs in the sky. It’s an illusion formed between the sunshine, the rain and your eyes. Light bounces out of the raindrops at an angle of 40° for red light, and 42° for blue.
Why is called rainbow?
The word ‘rainbow’ originates from the Old English ‘renboga’ – ‘regn’ meaning ‘rain’ and ‘boga’ meaning ‘bow’. Imagine the arch shape an arrow might make when flying through the air, or the way your body curves when you bow down – both meanings of ‘bow’ descend from the Proto-Germanic ‘bugan’.
Is it rare to see the end of a rainbow?
If you’ve ever fantasized about finding the elusive pot of gold at the end of a rainbow, you’re about to be sorely disappointed. Because finding the true end of a rainbow is about as unlikely as stumbling across an unclaimed cauldron of gold doubloons.
These pictures may come close—but what they really capture is one of nature’s greatest optical illusions. Rainbows are formed when water droplets in the atmosphere refract, or bend, sunlight in just the right circumstances. But you, as the observer, have to catch them just from the right angle and point of view as well in order to see them.
Most people don’t realize that whenever you see a rainbow, the sun is directly behind you — and the rain in front. (MORE: Fall Sunsets to Take Your Breath Away) Not only do the weather conditions have to be correct where you’re standing, but according to the National Center for Atmospheric Research, you also have to be standing at exactly the right angle (42 degrees) relative to the sun’s rays. It’s that very specific angle you have to be at to observe the phenomena that also explains why all the rainbow chasing in the world won’t get you to the pot of gold.
Consider this: If you see a friend standing directly underneath a rainbow and try to approach her, the closer you get, the father away the rainbow will appear. In fact, from her position, your friend will see an entirely separate rainbow in the distance — but still at 42 degrees. In fact, as far as scientists are concerned, no two people can even see the same rainbow (except in a photo!), since the effect is dependent on our own line of sight.
That means that no matter how hard you try, you can never get close enough to a rainbow to see its “end.” But don’t despair: Depending on how you look at it, it could also mean that there are an infinite number in the sky when the conditions are just right.
Can planes fly through rainbows?
No, you can’t fly over a rainbow – that would break the laws of physics Scientists can rest easy. Colourful “rainbow” pictures do not break the laws of physics. The airline passenger Melissa Rensen, from London, Canada, took the photographs out of an aircraft window as she flew over the Caribbean Sea.
Only later did she realise that the shots made it look like the plane was flying over a rainbow. The pictures sparked a flurry of news stories about her literally flying over a rainbow. But according to physics, this is impossible. Rainbows are formed when sunlight hits water droplets in the atmosphere.
The water splits the sunlight into its constituent colours and reflects them at an angle of about 42 degrees, causing the rainbow to appear in the sky. The rainbow is an optical illusion that depends upon the angle between the sun, the droplet and the observer remaining constant at 42 degrees.
So it is impossible to see a rainbow in front of you and then be able to fly over it because as the angles change, the rainbow phenomenon will disappear or reappear in a different place. There could be situations when a rainbow appears briefly to one side or below a plane if the angles all add up right but that is not the case here.
So what caused the colours in Rensen’s photographs? It all comes down to a property of the aircraft’s window known as birefringence. Plastic in an aircraft’s window displays the property of birefringence. This splits light entering it into two distinct rays.
The two rays have their colours dispersed differently as well. As the light emerges from the window, the two rays of light interfere with each other creating the coloured bands. The effect is most obvious when a polarising filter is used on the camera taking the picture. The ocean surface also acts like a polarising filter.
When sunlight reflects from the water, it becomes polarised. This means that the rays of light are made to oscillate in a predominant direction. Daylight is also polarised because it has been scattered by the molecules of the Earth’s atmosphere. Blue light is scattered more effectively than red light, which is why the sky is blue.
Has anyone ever touched a star?
Is it possible to touch stars with our bare hands? No. While none exist to date it would be possible for a dead star to have cooled to a safe temperature. However, such objects are inherently supported by degeneracy pressure-they’re very dense. Very heavy & very dense = very high surface gravity (typically 300,000+g.) While you’re not burned you’re squashed.
The low mass limit for a brown dwarf is 13 times Jupiter’s mass. However, Jupiter is about as big as such things get, piling on more mass increases the pressure enough the size stays about constant. Jupiter’s gravity is already 2.5g, for a constant size surface gravity scales linearly with mass, so a brown dwarf should have a surface gravity upwards of 30g.
You’re not quite so squashed as you were on the dead star but you’re still squashed. : Is it possible to touch stars with our bare hands?
Has there ever been 3 rainbows?
What about triple rainbows? – “First, yes, they exist”, clarifies Hwong. “Yet, a true third-order rainbow should not be confused with the much more common phenomena of supernumerary bows and reflection rainbows.” Third-order or tertiary rainbows originate from three reflections inside the droplet.
In contrast to primary and secondary bows, rays leave the droplet heading away from the sun. Hence, to see a tertiary rainbow, one must look towards the sun. However, at an intensity only one fourth of the primary arc, the bright sunlight makes the rainbow almost impossible to spot. It was only in 2011, in the journal Applied Optics, that first photographic evidence was published.
So, stay vigilant for rainbows – you may discover something new. Image above: Various kinds of multiple rainbows. Supernumerary bows (left) are caused by interference and reflection rainbows (middle) by water bodies reflecting the source of light. Third-order rainbows (right) are visible in the direction of the sun and very faint.
Is there gold at the end of a rainbow?
The old folktales tell us that there is a pot of gold hidden where the end of any rainbow touches the earth. Unfortunately, science tells us that rainbows do not have an end since their arch shape is an illusion!
What are rainbows made of?
How Are Rainbows Formed? Over the last couple of months, you may have noticed rainbows appearing frequently on social media and in your local neighbourhood. At the beginning of the coronavirus pandemic in the UK, children were encouraged by their schools and preschools to paint rainbows and display them at home on their windows as a message of hope and solidarity during uncertain times. A lovely painting of a rainbow by one of the RMetS staff children Rainbows are one of the most admired meteorological phenomena across the globe, but how are they formed? Rainbows are formed when light from the sun is scattered by water droplets (e.g.
Why is a rainbow 42 degrees?
The Path of Light Through a Droplet – A collection of suspended water droplets in the atmosphere serves as a refractor of light. The water represents a medium with a different optical density than the surrounding air. Light waves refract when they cross over the boundary from one medium to another. There are countless paths by which light rays from the sun can pass through a drop. Each path is characterized by this bending towards and away from the normal. One path of great significance in the discussion of rainbows is the path in which light refracts into the droplet, internally reflects, and then refracts out of the droplet.
The diagram at the right depicts such a path. A light ray from the sun enters the droplet with a slight downward trajectory. Upon refracting twice and reflecting once, the light ray is dispersed and bent downward towards an observer on earth’s surface. Other entry locations into the droplet may result in similar paths or even in light continuing through the droplet and out the opposite side without significant internal reflection.
But for the entry location shown in the diagram at the right, there is an optimal concentration of light exiting the airborne droplet at an angle towards the ground. As in the case of the refraction of light through prisms with nonparallel sides, the refraction of light at two boundaries of the droplet results in the dispersion of light into a spectrum of colors. The angle of deviation between the incoming light rays from the sun and the refracted rays directed to the observer’s eyes is approximately 42 degrees for the red light. Because of the tendency of shorter wavelength blue light to refract more than red light, its angle of deviation from the original sun rays is approximately 40 degrees.
- As shown in the diagram, the red light refracts out of the droplet at a steeper angle toward an observer on the ground.
- There are a multitude of paths by which the original ray can pass through a droplet and subsequently angle towards the ground.
- Some of the paths are dependent upon which part of the droplet the incident rays contact.
Other paths are dependent upon the location of the sun in the sky and the subsequent trajectory of the incoming rays towards the droplet. Yet the greatest concentration of outgoing rays is found at these 40-42 degree angles of deviation. At these angles, the dispersed light is bright enough to result in a rainbow display in the sky.
Is a rainbow a real or virtual image?
Both primary and secondary rainbows are virtual images.
Is the shape of a rainbow a polygon?
As the definition tells us, a polygon’s sides must be straight. If any side is curved, then it’s no longer a polygon. So, the moon, the sun and rainbows are not polygons because they are curved.