Doppler effect
Concept
The change in frequency of a wave (like sound in ultrasound) in relation to an observer who is moving relative to the wave source, used in echocardiography to show blood flow.
Mentioned in 2 videos
Videos Mentioning Doppler effect

The Science of Hearing, Balance & Accelerated Learning
Andrew Huberman
The change in frequency or wavelength of a sound (or light) in relation to an observer who is moving relative to the source of the sound, used by the brain for sound localization and by bats for echolocation.

#61–Rajpaul Attariwala, M.D., Ph.D: Cancer screening with full-body MRI & a masterclass in radiology
Peter Attia MD
The change in frequency of a wave (like sound in ultrasound) in relation to an observer who is moving relative to the wave source, used in echocardiography to show blood flow.