Christian Doppler was an Austrian mathematician and physicist, who gave the principle of ‘Doppler Effect’, which states that observed frequency of a wave depends on the relative speed of the source and the observer. Doppler was born into a middle class family of stonemasons. From his childhood, he was of frail health, which made him unfit for a stonemason’s job. At the age of 18, he was sent to Vienna to study at the Polytechnic Institute so that he could be trained for some other business. But it was here that Doppler realized the importance of education. He, therefore, returned home to complete his studies at the gymnasium, after which he enrolled at the University of Vienna, finally graduating at the age of 26. Thereafter, he held various academic posts, publishing number of papers, initially in mathematics and then in physics. His most notable work, published at the age of thirty-nine, is today known as ‘Doppler Effect’ or ‘Doppler Shift’. Unfortunately, he did not live long, and died at the age of 49 from a pulmonary disease.
