| Please help improve this article by adding reliable references.For other uses, see Rainbow (disambiguation).Rainbows are optical and meteorological phenomena that cause a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere.They take the form of a multicoloured arc, with red on the outer part of the arch and violet on the inner section of the arch.More rarely, a secondary rainbow is seen, which is a second, fainter arc, outside the primary arc, with colours in the opposite order, that is, with violet on the outside and red on the inside.Biv" and "Richard Of York Gave Battle In Vain" are popular mnemonics.Visibility
2 Scientific explanation
3 Variations
3.Rainbows may also form in the spray created by waves.Rainbows can be observed whenever there are water drops in the air and sunlight shining from behind a person at a low altitude or angle (on the ground).The most spectacular rainbow displays happen when half of the sky is still dark with draining 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.The rainbow effect is also commonly seen near waterfalls or fountains.You can create your own rainbow by facing 180 degrees from the sun and spray mist from a garden hose in front of you in a circular motion, outlining a 360 degree "rainbow".From an aeroplane, one has the opportunity to see the whole circle of the rainbow, with the plane's shadow in the centre.Scientific explanation
The rainbow's appearance is caused by dispersion of sunlight as it goes through raindrops.The light is first refracted as it enters the surface of the raindrop, reflected off the back of the drop, and again refracted as it leaves the drop.The 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 'rain'bow in sea spray is smaller than a true rainbow.This is visible to the naked eye by a misalignment of these bows.Blue light (shorter wavelength) is refracted at a greater angle than red light, but because the area of the back of the droplet has a focal point inside the droplet, the spectrum crosses itself, and therefore the red light appears higher in the sky, and forms the outer colour of the rainbow.However, light coming out the back of the raindrop does not create a rainbow between the observer and the sun because spectra emitted from the back of the raindrop do not have a maximum of intensity, as the other visible rainbows do, and thus the colours blend together rather than forming a rainbow.Light rays enter a raindrop from one direction (typically a straight line from the Sun), reflect off the back of the raindrop, and fan out as they leave the raindrop.The light leaving the rainbow is spread over a wide angle, with a maximum intensity of 40.White light separates into different colours (wavelengths) on entering the raindrop because red light is refracted by a lesser angle than blue light.On leaving the raindrop, the red rays have turned through a smaller angle than the blue rays, producing a rainbow.This light is what constitutes the rainbow for that observer.The position of a rainbow in the sky is always in the opposite direction of the Sun with respect to the observer, and the interior is always slightly brighter than the exterior.Exceptions occur when the observer is high above the ground, for example in an aeroplane (see below), on top of a mountain, or above a waterfall.Some light reflects twice inside the raindrop before exiting to the viewer.Alexander's band between the bows.Occasionally, a second, dimmer, and thicker secondary rainbow is seen outside the primary bow.As a result of the second reflection, the colours of a secondary rainbow are inverted compared to the primary bow, with blue on the outside and red on the inside.These rainbows would appear on the same side of the sky as the Sun, making them hard to spot.One type of tertiary rainbow carries with it the appearance of a secondary rainbow immediately outside the primary bow.The closely spaced outer bow has been observed to form dynamically at the same time that the outermost (tertiary) rainbow disappears.During this change, the two remaining rainbows have been observed to merge into a band of white light with a blue inner and red outer band.This particular form of doubled rainbow is not like the classic double rainbow due to both spacing of the two bows and that the two bows share identical normal colour positioning before merging.With both bows, the inner colour is blue and the outer colour is red.Sassan in 1979 using a HeNe laser beam and a pendant water drop.Primary and secondary rainbows are visible, as well as a reflected primary and a faintly visible reflected secondary.Supernumerary rainbows
A supernumerary rainbow is an infrequent phenomenon, consisting of several faint rainbows on the inner side of the primary rainbow, and very rarely also outside the secondary rainbow.Supernumerary rainbows are slightly detached and have pastel colour bands that do not fit the usual pattern.The alternating faint rainbows 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 similar 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.Other rainbow variants are produced when sunlight reflects off a body of water.Where sunlight reflects off water before reaching the raindrops, it produces a reflection rainbow.Such a rainbow shares the same endpoints as a normal rainbow but encompasses a far greater arc when all of it is visible.Both primary and secondary reflection rainbows can be observed.In Europe, the work of Robert Grosseteste on light was continued by Roger Bacon, who wrote in his Opus Majus of 1268 about experiments with light shining through crystals and water droplets showing the colours of the rainbow.Theodoric of Freiberg is also known to have given an accurate theoretical explanation of both the primary and secondary rainbows in 1307.He explained the primary rainbow, noting that "when sunlight falls on individual drops of moisture, the rays undergo two refractions (upon ingress and egress) and one reflection (at the back of the drop) before transmission into the eye of the observer".He explained the secondary rainbow through a similar analysis involving two refractions and two reflections.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, 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.Isaac Newton was the first to demonstrate that white light was composed of the light of all the colours of the rainbow, which a glass prism could separate into the full spectrum of colours, rejecting the theory that the colours were produced by a modification of white light.He also showed that red light gets refracted less than blue light, which led to the first scientific explanation of the major features of the rainbow.Newton's corpuscular theory of light was unable to explain supernumary rainbows, and a satisfactory explanation was not found until Thomas Young realised that light behaves as a wave under certain conditions, and can interfere with itself.Young's work was refined in the 1820s by George Biddell Airy, who explained the dependence of the strength of the colours of the rainbow on the size of the water droplets.Modern physical descriptions of the rainbow are based on Mie scattering, work published by Gustav Mie in 1908.Advances in computational methods and optical theory continue to lead to a fuller understanding of rainbows.The end of a rainbow.The rainbow has a place in legend owing to its beauty and the historical difficulty in explaining the phenomenon.In Greek mythology, the rainbow was considered to be a path made by a messenger (Iris) between Earth and Heaven.In Hindu mythology, the rainbow is called Indradhanush, meaning the bow of Indra, the God of lightning and thunder.Midgard, homes of the gods and humans, respectively.The Irish leprechaun's secret hiding place for his pot of gold is usually said to be at the end of the rainbow.This place is impossible to reach, because the rainbow is an optical effect which depends on the location of the viewer.When walking towards the end of a rainbow, it will move further away.In the Biblical Canon of Christian and Jewish scripture, the rainbow is explicitly stated as a sign of the Noahic Covenant between God and The Creation, and the biblical God's promise to Noah that never again would The World be purified by the Deluge (Genesis 9.When I bring clouds over the earth and the bow is seen in the clouds, I will remember my covenant that is between me and you and every living creature of all flesh; and the waters shall never again become a flood to destroy all flesh.Art
The rainbow occurs often in paintings.In particular, the rainbow appears regularly in religious art (for example, Joseph Anton Koch's Noah's Thanksoffering).Literature
The rainbow inspires metaphor and simile.So be it when I shall grow old,
Or let me die!The Newtonian deconstruction of the rainbow is said to have provoked John Keats to lament in his 1820 poem "Lamia":
Do not all charms fly
At the mere touch of cold philosophy?In the dull catalogue of common things.Unweaving the Rainbow: Science, Delusion and the Appetite for Wonder:
"My title is from Keats, who believed that Newton had destroyed all the poetry of the rainbow by reducing it to the prismatic colours.Popular culture
The rainbow has been used in many contemporary settings, such as the song "Over the Rainbow" in the musical film The Wizard of Oz and the song "The Rainbow Connection" from The Muppet Movie.In Britain, one of the most popular children's shows in the 1970s and 1980s was the Thames TV production Rainbow.The Greenpeace ship, Rainbow Warrior, was named after a Cree Native American prophecy that stated "When the world is sick and dying, the people will rise up like Warriors of the Rainbow."The Rainbow Coalition is a local social action group that was started in Chicago, Illinois by Jesse Jackson from which he launched his national political and social reform platform.Rainbow Gatherings are gatherings of hippies who come together on public lands with a stated mission to espouse the ideas of peace, love, freedom and community.Flags
See main article Rainbow flag.Historically, a rainbow flag was used in the German Peasants' War in the 16th century as a sign of a new era, of hope and of social change.Rainbow flags have also been used as a symbol of the Cooperative movement; as a symbol of peace, especially in Italy; to represent the Tawantin Suyu, or Inca territory, in Peru and Ecuador; by some Druze communities in the Middle east; and by the Jewish Autonomous Oblast.Biv mnemonics follow the tradition of including the colour indigo between blue and violet.When to View and How to Photograph a "Moonbow".The Ansel Adams Gallery.Lindberg, David C (Summer, 1966)."Roger Bacon's Theory of the Rainbow: Progress or Regress?"."Descartes and the Radius of the Rainbow"."Did Kepler's Supplement to Witelo Inspire Descartes' Theory of the Rainbow?".Moyses, "The Theory of the Rainbow," Scientific American 236 (1977), 116.Reference Edition (with Old and New Testaments) (1990).Grand Rapids, Michigan: Zondervan Bible Publishers.Modern Art in the South."Roger Bacon's Theory of the Rainbow: Progress or Regress?"."However, most people can only discern six of these hues; they have trouble telling the difference between indigo and violet."References
Greenler, Robert (1980).Rainbows, Halos, and Glories.The Rainbow Bridge: Rainbows in Art, Myth and Science.The Rainbow, From Myth to Mathematics.National Center for Atmospheric Research, About Rainbows
Lez Cowly's Atmospheric Optics
Blake Ebersole's Rainbow Science
Supernumerary and Multiple Rainbows
About rainbows
Interactive simulation of light refraction in a drop (java applet)
Spectacular rainbow at Elam Bend (McFall, Missouri)
Walter Lewin's Discussion on colours and rainbow physics
Why are rainbows round?This page was last modified 20:41, 9 January 2008.All text is available under the terms of the GNU Free Documentation License.Rainbow was a children's television series in the United Kingdom which ran twice weekly at 12.American educational puppet series Sesame Street.On 28 February 2006, BBC News reported that digital children's channel Nick Jr.Rainbow (dating from 1982) on Mondays.Premise
Each episode of Rainbow revolved around a particular activity or situation that would arise in the Rainbow House, where the main characters lived.Usually it would involve some kind of squabble or dispute between the puppet characters of Zippy, George and Bungle, and Geoffrey's attempts to calm them down and keep the peace.The main story would be interspersed with songs (usually from Rod, Jane and Freddy, although guest singers would occasionally take their place), animations, and stories read from the Rainbow storybook, usually by Geoffrey.Some episodes would focus on a particular theme, such as sounds or opposites, and would consist mainly of short sketches or exchanges between the main characters, rather than a consistent storyline.David Cook, then the best known presenter Geoffrey Hayes), who brought them to order or gave them something to do.John Leeson, Stanley Bates, Malcolm Lord, Paul Cullinan).The question regarding why Bungle always wrapped a towel around his waist to protect his modesty after a shower, in spite of the fact that he walked around nude for the rest of time, has never been addressed.He also donned pyjamas at bed time.Sunshine (yellow with a red hat) and her more gloomy friend Moony (brown with a tuft of yellow hair) were the original 'stars' of the programme, but soon became little more than foils to the more popular Zippy; they were phased out by 1973, in favour of greater roles for Bungle and (especially) George.Rod, Jane and Freddy, a group of musicians who regularly featured on the programme.Rod, Jane and Freddy took over.Zippo, Zippy's cousin, identical in appearance to Zippy, who would make the occasional guest appearance.Dawn Bowden, who was introduced in the show's later years, first appearing in 1986.He seemed to be some sort of a brother to Geoffrey.Generally speaking, George and Zippy represented two 'types' of child, George being the quiet and shy type, while Zippy represented the hyperactive and destructive type (hence his name).George was usually vindicated, but Zippy got his comeuppance.Apart from Jane and (in the early days) Sunshine, females rarely appeared on the programme, despite some ambiguity concerning the often effeminate (and permanently pink) George.In 1989, Rod, Jane and Freddy left the show to concentrate on touring, pantomime appearances and their own separate TV show.This meant that Dawn Bowden was introduced as a regular female character in place of Jane, while the songs were generally provided by guest singers, notably Christopher Lillicrap.Theme Song
The theme song for the show was actually a small part of the full version, also called 'Rainbow' and written by Hugh Portnow, Hugh Fraser and Tim Thomas.The full lyrics to the song are:
Up above the streets and houses,
Rainbow climbing high,
Everyone can see it smiling
Over the sky.Paint the whole world with a rainbow.All along the streams and rivers,
Shining in the lakes,
See the colours of the rainbow
As the morning breaks.Paint the whole world with a rainbow.Take some green from a forest,
Blue from the sea,
Find the misty pot of gold,
And mix them for a week.Paint the whole world with a rainbow.Red, the colour of a sunrise,
White clouds floating in a sky of blue,
Green for the rivers,
Gold for the cornfields,
The day is shining new.The revival
Although the original Rainbow ended with the loss of Thames' broadcasting licence in 1992, Tetra Films (an independent production company spawned by Thames' children's department) revived it for ITV in 1994.Cleo (voiced by Gillian Robic).Rainbow Days, presented by Dale Superville.The "adult" version
In 1979, the cast and crew of Rainbow made a special edition for the Thames TV staff Christmas tape, sometimes referred to as the "Twangers" episode.This show featured plenty of intended sexual innuendo (beginning with Zippy peeling a banana, saying "One skin, two skin, three skin, four..."Geoffrey alongside exaggerated versions of Bungle and the puppets, which contained some mild sexual innuendo.Davro had appeared in a regular edition of the show, in which he performed amusing impressions of the characters in front of them.While not explicitly adult most interviews featuring Zippy and George after the show braodcast commonly portray them as somewhat more edgy in terms of personality.For example, in an episode of SMTV live they call Bungle an, "Idiotic, blundering creature."This page was last modified 13:46, 2 January 2008.All text is available under the terms of the GNU Free Documentation License.See Copyrights for details.Put some content here to tell the user what's going on
while they wait.OR BROWSERS THAT HAVE THEIR SCRIPTING TURNED OFF...IF YOU ARE USING PAGE REDIRECT, A META REFRESH GOES HERE.DELETE EVERYTHING BETWEEN THE NOSCRIPT TAGS
EXCEPT YOUR alternateContent HTML.Locate a Rainbow FactoryShowroom near you!Imagine the exhilarating fun your kids will have with castles, forts, clubhouses, a general store, a playhouse, climbing walls, monkey bars ...Rainbow wooden swing sets.Even though the options and accessories seem overwhelming, choosing your Rainbow Play Systems wooden swing set is easy.The creators and designers at Rainbow Play Systems make sure the fun and flight of imagination is firmly grounded with quality construction and safety, giving you a wooden swing set you can trust and your kids can enjoy for years.It's the fact that you'll find ALL these promises under one Rainbow.We absolutely love our Rainbow!It has been a quality investment that is creating a lifetime of memories for our entire family.There is no substitute for a Rainbow.Rainbow Play Systems Inc.Rainbow
Rainbow
Rainbow is a program that performs statistical
text classification.This documentation is intended as a brief tutorial for using
rainbow, version 0.It
is not a tutorial on the source code.The examples on this page assume that you have compiled libbow and
rainbow, and that rainbow is in your path.Introduction
The general pattern of rainbow usage is in two steps (1) have rainbow
read your documents and write to disk a "model" containing their
statistics, (2) using the model, rainbow performs classification or
diagnostics.Bow library
frontends are handled by the libargp library from the FSF.For more detail about the verbosity option, see section 5.The testing data may also be read as part of the model, or it can be
left out and read later.The model name is actually a
file system directory containing separate files for different aspects
of the model.If the model directory location does not exist when
rainbow is invoked, rainbow will create it automatically.Thus, for example, you should be able
to index a directory of UseNet articles or MH mailboxes without any
preprocessing.The files should be organized in directories, such that all documents
with the same class label are contained within a directory.Rainbow
does not directly support classification tasks in which individual
documents have multiple class labels.Tokenizing Options
When indexing a file, rainbow turns the file's stream of characters
into tokens by a process called tokenization or "lexing".Otherwise, include this token among the
statistics, and read the next token.Rainbow supports several options for tokenizing text.Which
should be used for the 20_newsgroups dataset, since the headers
include the name of the correct newsgroup!Pass all words through the Porter
stemmer before counting them.The default is to skip them.The stoplist is the SMART
system's list of 524 common words, like "the" and "of".Useful for lexing HTML
files.Classifying Documents
Once indexing is performed and a model has been archived to disk,
rainbow can perform document classification.Bow source distribution, reads lines like this and outputs average
accuracy, standard error, and a confusion matrix.Trial 1
Correct: 1086 out of 1201 (90.To give you some idea of the speed of rainbow: On a 200 MHz
Pentium, the above rainbow command finishes in 14 seconds.Note, however, that several internal variables are of type
float, (which has only about 7 digits of resolution) and the
classification scores are calculated as double's, (which has
only about 17 digits of resolution), so precision is inherently
limited.The default printed score precision is 10.If the number argument is followed by "pc", then the
arguments indicates a number of documents per class.You can also specify exactly which files should be in the test set,
listing them by name.The list of filenames should be named as they where then the model
was built.It is an error for a
document to be listed in both the test set and the train set.Rainbow Classification as a Server
Rainbow can also efficiently classify individual documents not in
the model by running as a server.In this mode, rainbow starts, reads
the model from disk, then waits for query documents by listening on a
network socket.PORT (where PORT is some port number
larger than 1000).In order to test the server, telnet to whatever port you specified
(e.Rainbow will then print back to the socket (and thus to your
screen) a list of classes and their scores.Remove words that occur in N or fewer documents.Remove words that occur less than N times.Selecting the Classification Method
Rainbow supports several different classification methods, (and the
code makes it easy to add more).TFIDF, and probabilistic indexing are all
available.EVENTNAME can be one of:
word (i.The above is calculated using all the training data.To restrict the
calculation to a subset of the data, use any of the methods for
defining the training set described in section 3.For example, the
following command will print the word probabilities in the
talk.Here is the output of this command.Notice that the word
probabilities correctly sum to one.For
example, the following command prints diagnostics about the word
team.Here is the output on the above command, on a model built from
20_newsgroups.Note that the word probabilities (in
parenthesis) may not simply be equal to the ratio of the two previous
counts because of smoothing.Document filenames are printed in
the order in which they were indexed.For example, the following command prints 10 randomly selected
documents that were indexed.In order to obtain a random
selection, gawk, the GNU version of awk, is used
to generate random numbers, and sort is used to permute the
list.The command head is then used to select the first 10
from the permuted list.How to indicate the word itself.Verbosity of Progress Messages
Rainbow prints messages about its progress to standard error as it
runs.The argument
LEVEL should be an integer from 0 to 5, 0 being silent (no
progress messages printed to standard error), and 5 being most
verbose.Some of the progress messages print backspace characters in order
to show running counters.When running rainbow with GDB inside an
Emacs buffer, however, the backspace character is printed as a
character escape sequence and fills the buffer."This page requires AC_RunActiveContent.Commands menu to copy AC_RunActiveContent.Commands menu to copy AC_RunActiveContent.About the Rainbow ProjectThe Rainbow project is an open source initiative to build a comprehensive content management system using Microsoft's ASP.XML news feeds, Flash, Maps, Newsletter, Surveys, Forums, Document Management, Custom Lists, and more.It's also fairly easy to build your own custom modules using the guidelines provided on the Developer Documentation page.Rainbow has received more than 156,000 downloads to date and more downloads of the new ASP.Rainbow is already in production at many commercial internet and intranet sites.Learn more about Rainbow.The Rainbow Team has released a new version of Rainbow that runs on the ASP.Commerce 'Product Module' user guide.SearchNews ArchiveManu's NewsletterReviewsGuestMAPWhat is this?This service is provided for free and based on GoogleEarth..Logged in users have access to more downloads.Please register for a free Rainbow account if you have not done so.Rainbow logoThis site is, of course, built using Rainbow.Feel free to add the new logo to your sites powered by Rainbow.LearnASP
Support UsHi guys: we are working hard to give you Rainbow code free of charge.This will help us to pay bills.Simply press the "Donate" button to go to Paypal Payment System.At Rainbow Grocery, our purpose is to provide natural, organic, vegetarian food and environmentally and health conscious products at an affordable price.Beets, Cabbage, Guava, and Swiss Chard...At the Loading Dock on Trainor Alley
between 13th and 14th streets
*Must show Membership Card.Find out more about BicycleR Evolution at bikerev.Find out more about BicycleR Evolution at bikerev.Rainbow Grocery will be closed on March 30th to honor the life and legacy of Cesar E.We will also participate in the 2007 Cesar E.We discussed the effects of sugar on health, how to identify hidden sugars in food, the primary causes of cravings, and simple steps for dealing with sugar addiction.Be on the lookout for future lectures.Enter to win a bicycle trailor by BicycleR Evolution.The drawing box is in the customer seating area
near our Folsom Street entrance.New Discount for Bicyclists !!San Francisco Bicycle Coalition
(with current membership card and valid picture I.Just click here to download a PDF.Rainbow is now listedin the San Francisco Greenopia Guide and on their website at:
greenopia.Read many pages
of Rainbow Grocery reviews
Rainbow gets a 4.Rainbow Grocery Cooperative Statement
Regarding Boycott on Israeli Goods
As you may be aware, an organization, BIG (Boycott Israeli Goods), has made public statements regarding Rainbow Grocery participating in a boycott on products from Israel.In order to clarify Rainbow Grocery's position on boycotting Israeli goods, we are releasing this statement to communicate to our clients and our community that there has been no decision to enact a boycott on Israeli products.While it is still too soon to know exactly the impact of this winter's cold temperatures, there are some things we do know.California citrus and vegetable production has been hit hard by the record cold temperatures.Reports from growers in the lower San Joaquin, Coachella and Imperial Valleys tell of repeated days of record lows, harvest crews that can not start working till noon and widespread frost damage on leafy crops and citrus.In the short term it will mean rising prices, decreased availability and quality problems.It has also been very hard to continue planting something that is essential to continue the unbroken flow of product.Organic Baby Clothes
Rainbow Grocery now carries organic cotton baby clothes and towels.If your timing is right, you may be able to meet Mara, Rainbow's gardener.Tell Governor Schwartzenegger
to limit perchlorate levels in our drinking water!Rainbow Grocery sales and events. |
