Development
Doppler first proposed the effect in 1842 in his treatise "Über das farbige Licht der Doppelsterne und einiger anderer Gestirne des Himmels" (On the coloured light of the binary stars and some other stars of the heavens). The hypothesis was tested for sound waves by Buys Ballot in 1845. He confirmed that the sound's pitch was higher than the emitted frequency when the sound source approached him, and lower than the emitted frequency when the sound source receded from him. Hippolyte Fizeau discovered independently the same phenomenon on electromagnetic waves in 1848 (in France, the effect is sometimes called "l'effet Doppler-Fizeau" but that name was not adopted by the rest of the world as Fizeau's discovery was three years after Doppler's). In Britain, John Scott Russell made an experimental study of the Doppler effect (1848).
Read more about this topic: Doppler Effect
Famous quotes containing the word development:
“Information about child development enhances parents’ capacity to respond appropriately to their children. Informed parents are better equipped to problem-solve, more confident of their decisions, and more likely to respond sensitively to their children’s developmental needs.”
—L. P. Wandersman (20th century)
“Somehow we have been taught to believe that the experiences of girls and women are not important in the study and understanding of human behavior. If we know men, then we know all of humankind. These prevalent cultural attitudes totally deny the uniqueness of the female experience, limiting the development of girls and women and depriving a needy world of the gifts, talents, and resources our daughters have to offer.”
—Jeanne Elium (20th century)
“Fascism, the more it considers and observes the future and the development of humanity, quite apart from political considerations of the moment, believes neither in the possibility nor the utility of perpetual peace.”
—Benito Mussolini (1883–1945)