Rainbow is that sunlight
refraction and reflection happened but takes form with certain angle irradiation on water-drop.
Rain has been all over in the queen , the sky small water-drop, this is one kinds of natural triple prism. , when sunlight permeates water-drop since
refraction composes in reply an opposite direction effect, be become seven coloured light , can see the beautiful arc as long as the sun angle is appropriate quilt decomposing.If only having tiny water-drop in air drying, or the sky, cannot only be capable to do the rainbow taking form. Come to say water-drop is
increasingly big , rainbow belt is increasingly narrow , the color is increasingly distinct the sort; Whereas, water-drop is increasingly small, rainbow belt is increasingly broad , the color is dim. Sometimes, we can see the sky have two strip rainbow: A bar shouts the host rainbow , a vivid shade , inside is purple , outside is red; Another a bar shouts subsidiary rainbow , inside is red , outside is purple,The rainbow color is thinner. This phenomenon is a reason since sunlight permeates two time of refraction happened and reflecting when water-drop.
The rainbow that we see all is crooked, but not straight this be why?
Cause one: Glossy curved degree the wavelength glorifying is decided
In the sky, all small water-drop all arrange on a circumference. Water-drop and the sun , relative location of person eye on the circumference are all each other simultaneous, from colour light , ability that refraction produces in these water-drop cast on to person in self''s eyes. Think that are colour light produced by these water-drop when congregate together, people can see a colourful color light band just now.
When cutting through water-drop only curved degree, the bending degree holding the wavelength (be colour) looking at up but fixing red up is maximal , the orange takes second place only only with the yellow , bending is purple up on the analogy of this, be short most. Colour per kind has the specially appointed curved angle respectively , red in sunlight anaclasis''s, the angle is 42 degree , the refraction angle that blue glorifies only has 40 degree, therefore every kind of colour location appearing middle in the sky is different.
The angle because of anaclasis respectively different , therefore seven kinds colour are able to arrange thereby very beautifully with each''s different angle refraction because of colour. Appear because of rainbow in the sky opposite to sun direction , be going with back facing being burning therefore thinking of when looking at rainbow behind rain sun.
Cause two: Have very big something to do with terrestrial form
Since the earth surface is that one curved surface is covered by thick atmosphere moreover , water contents in rain queen air is higher than ordinary time, while sunlight irradiates small water-drop in entering air have formed refraction right away. Because the earth surface atmospheric layer is one cambered surface have led to the sunlight at the same time have formed arc rainbow that our saw in surface refraction!