Police sirens change pitch when going past us due to the Doppler effect. This phenomenon can also be used to measure speeds, even of faraway objects, like stars.
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Watch the full lecture: http://www.rigb.org/christmas-lectures/watch/1981/from-magna-carta-to-microchip/outwards-to-the-stars?utm_source=youtube&utm_medium=social&utm_term=description
RV Jones gave the 1981 Christmas Lectures "From Magna Carta to Microchip" which explores what measurement is, the principles by which measurements can be made, and why their applications have been of so much importance in the advance of science and in the development of technology
In his fourth lecture, RV Jones takes things to the extreme, and measures things that are very large or very far away.
Watch the full series: http://www.rigb.org/christmas-lectures/watch/1981/from-magna-carta-to-microchip?utm_source=youtube&utm_medium=social&utm_term=description
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