Sound of very high frequency (greater than 20 kHz) is called ultrasound.
`"Properties"`
Sound wave of all frequencies carry energy with them, with increase in frequency, vibration becomes faster and also energy content and force increase. When ultrasound travels in solid, liquid and gas it subjects the particles of matter to face large force and energy.
`"Good directionality"`
Ultrasonic waves are able to travel along well defined straight paths, even in the presence of obstacles. Therefore, they are used for imaging objects.
`"Applications of ultrasound"`
• `"Welding metal"` They are used for welding metals like tungsten which cannot be welded by conventional methods.
• `"Medical purposes"` The ultrasonic vibrations can be reflected from the boundaries between the materials of nearly same density. The technique is used in scanning the internal organs of human body. It is superior to the X-ray scanning, as it does not cause any harm to human cells, unlike X-rays.
• The instrument which uses ultrasonic waves for getting the images of internal organs of human body is called ultrasound scanner. In this technique, the ultrasound waves travel through the tissues of the body and get reflected from the region where there is change in density. These reflected waves are then converted into electrical signals. 'These signals are then displayed on TV monitor or can be printed on a film. This technique is called ultrasonically and help doctors to detect abnormalities, such as stone in gall bladder and kidney or tumors in different organs.
• Ultrasound waves of high intensity are employed to break small stones in the kidney into fine grains. The fine grains then get flushed out with urine.
• Echocardiography is a technique in which ultrasonic waves, reflected from various parts of heart form an image of the heart.
• `"Drilling holes or making cuts of desired shape"` We can use a hammer and a steel punch to make holes in metal plates, plastic sheets or other solid materials. Such holes can also be made using ultrasonic vibrations produced in a metallic rod, called a horn.
• `"Ultrasonic cleaning"` For small parts such as used in watches, electronic components, odd-shaped parts such as a spiral tube and parts located in hard to reach places, this method is used. Such objects are placed in a cleaning solution and ultrasonic waves are sent into the solution.
• `"Ultrasonic detection of defects in metals"` If there are cracks or holes inside the metal, such defects are not visible from the outside. Ultrasonic waves can be used to detect such defects. Ultrasonic waves are sent through the metallic object under study. If there is no crack or cavity in its path, it goes through the object. A detector placed on the other side detects the transmitted wave. A defect present in the path of the wave reflects the wave.
• `"Bats"` fly in the darkness of night without colliding with other objects by the method of echolocation. Bats emit high frequency ultrasonic squeaks while flying and listen to the echoes produced by the reflection of their squeaks from the objects in their path. From the time taken by the echo to be heard, bats can judge the distance of the object in their path and hence avoid it by changing the direction. Bats search their prey at night by the method of echolocation.
Sound of very high frequency (greater than 20 kHz) is called ultrasound.
`"Properties"`
Sound wave of all frequencies carry energy with them, with increase in frequency, vibration becomes faster and also energy content and force increase. When ultrasound travels in solid, liquid and gas it subjects the particles of matter to face large force and energy.
`"Good directionality"`
Ultrasonic waves are able to travel along well defined straight paths, even in the presence of obstacles. Therefore, they are used for imaging objects.
`"Applications of ultrasound"`
• `"Welding metal"` They are used for welding metals like tungsten which cannot be welded by conventional methods.
• `"Medical purposes"` The ultrasonic vibrations can be reflected from the boundaries between the materials of nearly same density. The technique is used in scanning the internal organs of human body. It is superior to the X-ray scanning, as it does not cause any harm to human cells, unlike X-rays.
• The instrument which uses ultrasonic waves for getting the images of internal organs of human body is called ultrasound scanner. In this technique, the ultrasound waves travel through the tissues of the body and get reflected from the region where there is change in density. These reflected waves are then converted into electrical signals. 'These signals are then displayed on TV monitor or can be printed on a film. This technique is called ultrasonically and help doctors to detect abnormalities, such as stone in gall bladder and kidney or tumors in different organs.
• Ultrasound waves of high intensity are employed to break small stones in the kidney into fine grains. The fine grains then get flushed out with urine.
• Echocardiography is a technique in which ultrasonic waves, reflected from various parts of heart form an image of the heart.
• `"Drilling holes or making cuts of desired shape"` We can use a hammer and a steel punch to make holes in metal plates, plastic sheets or other solid materials. Such holes can also be made using ultrasonic vibrations produced in a metallic rod, called a horn.
• `"Ultrasonic cleaning"` For small parts such as used in watches, electronic components, odd-shaped parts such as a spiral tube and parts located in hard to reach places, this method is used. Such objects are placed in a cleaning solution and ultrasonic waves are sent into the solution.
• `"Ultrasonic detection of defects in metals"` If there are cracks or holes inside the metal, such defects are not visible from the outside. Ultrasonic waves can be used to detect such defects. Ultrasonic waves are sent through the metallic object under study. If there is no crack or cavity in its path, it goes through the object. A detector placed on the other side detects the transmitted wave. A defect present in the path of the wave reflects the wave.
• `"Bats"` fly in the darkness of night without colliding with other objects by the method of echolocation. Bats emit high frequency ultrasonic squeaks while flying and listen to the echoes produced by the reflection of their squeaks from the objects in their path. From the time taken by the echo to be heard, bats can judge the distance of the object in their path and hence avoid it by changing the direction. Bats search their prey at night by the method of echolocation.