A double rainbow!This amazing photo was taken by Wes Eisenhauer in Sioux Falls, South Dakota.The opt
A double rainbow!This amazing photo was taken by Wes Eisenhauer in Sioux Falls, South Dakota.The optical effect of a rainbow is formed as sunlight enters a raindrop. The beam of light is slowed down and is refracted, dispersed and reflected. Light essentially travels in waves of energy and appears white due to the combination of colours in that single wave of energy. When light bends individual colours will separate with violet light refracting the greatest and red light refracting the least.The critical angle of water is 48°, thus any light that hits the raindrop at an angle greater than this is internally reflected towards our eyes. Each ray of light is dispersed at a different angle, which causes the “bow” appearance.When a secondary rainbow appears, as in this photo, you will notice two things; firstly, the colour order is reversed and secondly the colours are not as sharp as in the primary rainbow.The reversal of the colour order is due to the fact that the ray of light is reflected twice within the raindrop. The second reflection inverts the order of the colours. Also attributed to the number of reflections; is the loss of intensity, with each reflection causing the bow to appear dimmer.JeanCue the ‘But what does it mean??’ comments in 3…..2….. -- source link
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