Sound, Radio & InformationWave Physics
The Doppler Effect
Motion changes the pitch of sound and the color of light
A siren wails past and its note sags mid-howl: neee-yowww. The siren never changed its tune. So who bent the note?
You'll find out
- Why a passing siren changes its note
- What the drop says about speed
- What makes distant galaxies look red
Why it matters
The same shift lets radar catch speeders, doctors watch blood flow, and astronomers see the universe expand.
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