Thursday, October 23, 2008

A rainbow is a natural phenomenon in which the colors of the spectrum appear in the sky in the form of an arc, caused by the refraction and reflection of the sun's ray when it shines onto small drops of moisture in the Earth's atmosphere. Rainbows can be seen when it is partially raining while the sun shines slantingly through a clearing in the clouds on raindrops, but the rainbow effect is also commonly observed near waterfalls or mist.

All raindrops refract and reflect the sunlight in the same way, but only the light from some raindrops reaches the observer's eye. The position of a rainbow in the sky is always in the opposite direction of the sun with respect to the observer. Thus, the rainbow apparent position depends on the observer's location and the position of the sun.