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Ultrasound

Ultrasound is sound pressure with frequency higher than 20khz; this is the upper frequency limit of human hearing. Since it is sound, it is a longitudinal wave.

Many animals such as bats and dogs have the ability to hear sounds with frequency above 20khz like bats and dogs. There are many human uses of ultrasound such as in the medical field to observe the body, ultrasonic testing to find out the density and shape of materials, SONAR and Ultrasonic cleaning

Medical sonography: A transmitter sends Ultrasound waves to the body which then reflects parts of or full waves back where the receiver uses the reflected waves to create an image of the organ or material it has bounced off. It is one of the most widely used diagnostic tools in modern medicine. Its is safe and poses no risk to the patient. However ultrasound energy produces pressure that causes minute bubbles of air which in turn causes distoration in the cells’ memebranes.
Ultrasound can also be used to detect abnormalities in the pelvis area. It also used to treat tumors using a process called Focused Ultrasound Surgery (FUS) or HIFU, High Intensity Focused Ultrasound.

Ultrasonic testing: It is a way of testing materials without damaging them in anyway way. Ultrasonic testing can be used to measure the thickness of materials as well as find flaws in them. An ultrasound transducer connected to a diagnostic machine is passed over the object. The waves reflected off the object is receive by the transducer and the diagnostic machine calculates the shape and thickness depending on the amplitude of the wave reflected. The distance of the part the wave reflected of is measured depending on the time it takes for the wave to arrive back.

SONAR(SOund NAvigation and Ranging): sonar is usualy used underwate by boats and submarines as navigation to detect the shape of the seabed or to detect other...