Bats navigate using ultrasound.
Sounds are waves produced from vibrating objects, such as violin strings. The rate of these wave vibrations is called the frequency. Ultrasound physics is the study of waves with very high frequencies.
Features
Ultrasonic waves occur at frequencies above 20,000 hertz. A hertz is one vibration per second. Human beings cannot hear ultrasound because the range of human hearing is from 20 to 20,000 hertz, though the upper limit decreases as a person ages.
Significance
Ultrasound has two primary uses. One is for navigation; for example, the Navy uses it in sonar systems for submarines. Sonar is short for sound navigation ranging. Ultrasound is also used to form images.
Images
The quality of ultrasound images depends on more than the initial frequency. An ultrasound wave in a body produces reflections that indicate the nature of the material and whether the reflection comes from object's surface or interior. These echoes have different frequencies if the object is moving. This is why ultrasound can be used to image brains, glands, bones, muscles and more.
Animals and Ultrasound
Animals such as bats emit ultrasound squeaks to find objects. Dolphins also use it to find objects and to scan images underwater. They are able to see inside living beings and reproduce these echoes to communicate the images to other dolphins.
Medicine
Medical practitioners use ultrasound, in frequencies from 1 to 20 million hertz, to produce images inside the body. For example, electrocardiograms image hearts, and sonograms monitor pregnant women.
Tags: find objects
