What makes a rainbow
Light
This radiant energy is released in the form of electromagnetic waves,
which travel unimpeded from the sun in straight lines at the speed of light-186,000 miles a second.Although the intensity of the en-ergy diminishes as it travels the 93million miles from the sun to Earth'sOuter atmosphere, the amount of energy received by Earth from the sun in ten seconds still is equivalent to all the electricity generated on the planet in one week. Electromagnetic waves vary In length, which is measured as the distance between the crests of waves.All the types of these waves together constitute the electromagnetic spectrum, which ranges fromextremely short ultraviolet waves to very longradio waves. Visible light, which occu-pies a narrow band of that spectrum,Comprises colors that vary in wavelength from short to long.Shorter wavelengths scatter more effectively in the atmosphere, which is why the sky is blue-a colorwitha relatively short wavelength-on asunny day. At dawn and dusk, light must passthrough more atmosphere, allowing
the longer orange and red light waves to predominate over the widely Scattered blue waves.
What makes a rainbow
The multicolored arc of a rainbow is produced by sunlight striking rain- drops beneath a rain cloud. Light refracts-bends-when it passes through drops of water. Each color of light refracts at a different angle: Violet bends more than blue, which bends more than green, and so on, with red refracting the least. If sunlight enters a raindrop at just the proper angle, it refracts, and its many Colors spread into a visible array.R Sunlight refracted through millions of raindrops forms a rainbow. On a primary rainbow, red is the outside color and violet the inside color. Occasionally a secondary rainbow appears slightly higher in the sky, and in it the colors of the rainbow are reversed (opposite). A rainbow's position in the sky depends on the sun's altitude above the horizon-the lower the sun, the higher the rainbow appears.
Colour of a rainbow ( by Wavelength)
Red:650 nanometres
Orange:600 nanometres
Yellow:580 nanometres
Green:550 nanometres
Cyan:500 nanometres
Blue:450 nanometres
Violet:400 nanometres
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