Albert Abraham Michelson was the first American scientist who received the Nobel Prize for Physics for his work on finding the speed of light. He designed and developed a device named ‘interferometer’ which could split a beam of light into two parts. The two parts of the same beam traveled at right angles to each other and were then brought together again. With his fellow scientist Edward Williams Morley he carried out an experiment with this device which is known as the ‘Michelson-Morley experiment’. The experiment helped him to conclude that the speed of light is 299,853 km per second. This figure remained the same for almost fifty years till he was able to design another device which produced a more accurate result. The speed of light was determined this time as 299,798 km per sec which was refined further to 299, 774 km per sec. He was also able to measure for the first time the size of the star ‘Betelgeuse’ to be 386,160,000 km with another special interferometer. He was unable to live to see the final results of his final experiment on the velocity of light which has been standardized. He also determined the length of the standard meter with the red light emitted by hot cadmium.