Not to be confused with Supersonic. Ultrasound pelvic ultrasound-to-child training sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances.
Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, who wrote on the mathematical properties of stringed instruments. In air at atmospheric pressure ultrasonic waves have wavelengths of 1.
Children can hear some high-pitched sounds that older adults cannot hear, because in humans the upper limit pitch of hearing tends to decrease with age. Bats use ultrasounds to navigate in the darkness. Many insects have good ultrasonic hearing and most of these are nocturnal insects listening for echolocating bats. The wild ancestors of cats and dogs evolved this higher hearing range to hear high-frequency sounds made by their preferred prey, small rodents. An ultrasonic level or sensing system requires no contact with the target. For many processes in the medical, pharmaceutical, military and general industries this is an advantage over inline sensors that may contaminate the liquids inside a vessel or tube or that may be clogged by the product.