Rainbow appears in the sky at the end of the rain. It is a long and wide band of seven colours. It forms a semicircle going from one end of the earth to the other. Scientists say that when sunlight passes through a thin medium to a denser medium, all the seven colours which are present in the white light form a semi-circular rainbow. The seven colours are violet, indigo, blue, green, yellow, orange and red. People believe that if a rainbow appears after the rain, it is an indication that there will be no more rains. In Hindi, rainbow is called 'Indra Dhanush' which means the Bow of Lord Indra. According to Hindu mythology Lord Indra is the god of rain. The rainbow looks miraculously beautiful. Its sight is very soothing to the eye. Small children get very excited when they see a rainbow.