Click on the photo
to see how the bleeps that dolphins send out work

Dolphins and whales use supersonic vibrations, in order to understand their environment, search for their food and detect objects underwater. For example, a dolphin can "see" a golf ball in a distance of 70 meters.

Inspired by dolphins, humans have constructed sonars (abbreviation from sound navigation and ranging). Firstly, they were used for spotting the enemies' submarines during the Second World War. But in any case, those tools are less effective than the natural sonars of dolphins.

A particular type of sonar is the "echo sounder" that is used in boats, in order to measure the sea depth, but also used from the fishermen, in order to track down shoals of fish.

A close look under the skin
The picture taking techniques with sound waves are also applied in the human body for the control of the good function of organs, such as the heart, the brain and the uterus. The basic principle of this function is the following: a source that emits supersonic vibrations is placed into the skin of the person examined; the thrusts propagate in the body and are reflected from the zones that have different thickness or toughness. Bones, for example, reflect better than other tissues, while moving blood transforms vaguely the frequency of the reflected sound wave. This phenomenon is known as the "Doppler phenomenon". The organ perceives all those differences, and with the help of a computer, it rehabilitates the internal anatomy of the body.

source: Internet-unknown