Day 82 of 365
March 23
⚛️
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!
Take Knowly with you
Get daily lessons, create your own, and build your personal wisdom library
Download for iOS