Ultrasound

Ultrasound: Sound with a higher frequency than we can hear. (above 20000Hz)

The range of human hearing is 20 to 20000Hz.

Used for: Ultrasonic scanning in medicine (parental scans of a baby in the womb), destruction of kidney stones.

Ultrasound waves are partly reflected at a boundary between two different types of body tissue. How ultrasound imaging works: 

• wave passes from one medium into another. some of the wave is reflected off the boundary and some is transmitted (refracted). This is partial reflection.
• You can point a pulse of ultrasound at an object and wherever there are boundaries between 1 substance and another, some of the ultrasound gets reflected back.
• time taken for reflections to reach a detector can…