Day 82 of 365
March 23
P
Physics The Doppler Effect
The Doppler effect causes wave frequency to change based on relative motion between source and observer. It's why ambulance sirens sound higher-pitched approaching and lower when receding. This principle applies to all waves - sound, light, water. Astronomers use Doppler shifts in starlight to detect exoplanets and measure cosmic expansion. Police radar guns and medical ultrasound also rely on the Doppler effect.
Did you know?
The entire universe's expansion was discovered through the Doppler effect - distant galaxies show redshift because they're moving away from us!
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