How does the ultrasound works?

Answer 1

Ultra-Beyond Sounds- sounds. it uses sonic waves beyond the frequency of human audibility hence it is not audible to normal hearing. Ultrasonic devices are surprisingly refined to 3D imaging like specialized Photography. It can see through human skin and systems far more accurately than X-rays and without radiation hazards.

Answer 2

Ultrasounds are defined as pressure waves in an elastic medium like air or a solid crystal with a frequency slight above the limit of human perception of sounds.

They are not heard by humans, but dogs for example can hear long wavelengths ultrasounds.

Since they are pressure waves they provoke a pressure alternate force on objects that they hit, thus they are used sometimes to clean jewels or other small and fragile thinks.

They are also used besides ordinary sounds in sonars to detect underwater objects due to the fact that they propagates underwater with small attenuation and are reflected by solid objects. Sonars uses a wide pressure waves band, formed both by audible sounds and by ultrasounds. Audible sounds have a smaller attenuation, but identify objects position with a smaller accuracy.

Some animals like bats have no eyes and uses ultrasounds to sense the environment.