the.com/ultrasound
sound so high you can't hear it, drawing pictures of the unborn and the unseen
frequencyAbove 20,000 Hz, past human hearing limits
bat techBats echolocated this way millions of years first
flaw finderUsed to spot cracks deep inside steel
cleaning powerUltrasonic baths scrub jewelry with collapsing bubbles
sonic surgeryFocused beams can destroy tumors without cutting skin