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Ever heard the high pitch of an ambulance siren, and notice that its pitch drops suddenly as the ambulance passes you? That's the Doppler effect. Here it is in action using a trombone and skis. The change in frequency or wavelength of a wave for an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842.
Posted 6 years ago by boyt in category: science   Comments (7)


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Bill Gates met with Nate Lewis, a Caltech professor who hopes to turn sunlight into fuel to power our cars, trains, and airplanes.
Posted 7 years ago by curley in category: science   Comments (2)


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Smarter Every Day
Posted 4 years ago by DETSCHS in category: science   Comments (2)



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The reaction of phosphoric acid with calcium contained in milk gives rise to a precipitate 3Ca + 2H3PO4 /// Ca3(PO4)2 + 3H2
Posted 9 years ago by anri1 in category: science   Comments (1)


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Posted 7 years ago by SugarJ in category: science   Comments (0)