Ultrasonic Sound or Ultrasound
The range of sound that can be heard clearly by a human being extends from about 20 Hz to 20000 Hz (one Hz = one cycle/s). Animals such as dogs and children under the age of five can hear up to 25 kHz (1 kHz = 1000 Hz). Ears of people will get less sensitive to higher frequencies as they grow old.
Infrasonic sound or infrasound
Frequencies of below 20 Hz sounds are called infrasonic sound or infrasound. Animals can listen to low-frequency infrasound's and can be getting disturbed by it. Before the main shock of an earthquake, the earth produces low-frequency infrasound's which are a disturbance to many animals. That is why many animals react and run for safe places before an earthquake. It is interesting to know that Rhinoceroses communicate using infrasound of frequency of 5Hz.
Ultrasonic Sound or Ultrasound
Sounds of frequencies higher than 20kHz are called Ultrasound or ultrasonic sound. Dolphins, bats, porpoises, and rats can produce ultrasonic sounds.
Applications of Ultrasound
Ultrasounds are used extensively in industries and for medical purposes. As mentioned above, Ultrasounds are high-frequency waves (higher than 20kHz). Even in the presence of obstacles, they are able to travel along well-defined paths.
- To clean parts located in hard to reach places, Ultrasound can be used. Ultrasonic waves are sent into the cleaning solution where the objects to be cleaned are placed. The particles of dust, dirt, and grease get detached and drop out due to the high frequency. This help to clean the objects thoroughly. Spiral tube, electronic components, and odd shaped parts are examples of such hard-to-reach objects.
- To detect cracks and flaws in metal blocks ultrasounds can be used. To ensure safety and quality of metal used in the manufacturing of machines, scientific equipment, bridges, and buildings etc., it is important to test the metal used before manufacturing the same. Detectors are used to detect the strength/quality of the metal blocks while ultrasonic waves are allowed to pass through it. Even a small defect can be identified by using the ultrasound test of metal objects.
- Doctors use the technique called Echocardiography in which ultrasonic waves are made to reflect from various parts of the heart and form image of the heart.
- Doctors also use an instrument called an ultrasound scanner for getting images of internal organs such as kidney, gall bladder, uterus, liver etc, of the human body. These images of internal organs help the doctor to detect the abnormalities such as tumors in different organs, stones in kidney and gallbladder etc. In this technique, ultrasonic waves travel through the tissues of the body and get reflected from a region where there is a change in tissue density. This technique is called 'ultrasonography'. Images of internal organs are printed in a film or displayed on a monitor. During the pregnancy, to detect congenital defects and growth abnormalities, doctors use ultrasonography to examine the fetus.
- Another use of ultrasound is to break small stones formed in the kidneys into fine grains. These grains later get flushed out with urine.
- Another use of ultrasound is in the Sound Navigation and Ranging (SONAR) It is a device that uses ultrasonic waves to measure the speed, direction, and distance of an underwater object. Sonar consists of a detector and transmitter which is installed in a ship or a boat. The transmitter emits ultrasonic waves and these waves travel through water. These ultrasonic waves get reflected back after striking the object on the seabed. The detector detects these waves and converts into electrical signals which are appropriately interpreted. The sonar technique is used to determine the depth of the sea and to locate icebergs, sunken ships, underwater hills, valleys, submarine etc.
- Bats search for its prey and fly in dark night by emitting and detecting reflections of ultrasonic waves. The nature of reflections of high-pitched ultrasonic squeaks of the bat tells where the obstacle or prey is and what it is like.
- For navigation and location of food in the dark, Porpoises also use ultrasound.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2012 Jacob
Furqan Azmi on November 17, 2018:
want to know what is ultrasonic frequency on which cats are repelled,
chinnu on December 12, 2017:
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Nabeel on December 21, 2016:
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Azina on November 25, 2016:
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aaliya on October 30, 2016:
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niara on August 04, 2016:
POSH on July 07, 2015:
CAN ANYONE TELL ME THE USE OF INFRASONIC SOUND??
thesi on May 22, 2015:
please tell some examples or uses of ultrasonic sound
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sharmeen on March 30, 2013:
can anyboy will tell me the uses of ultrasonic sound