What is ultrasound?

Ultrasound refers to the range of sound waves that have frequencies above human hearing.


(above 20,000 Hz)

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Can humans hear ultrasound?

No.

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Are there animals that can hear ultrasound?

Yes, some can (such as bats).

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What do bats use ultrasound for?

Communication and echolocating (to navigate and find prey).

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What device can we use to generate ultrasound?

A speaker.

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Is ultrasound harmful?

No, ultrasound is not harmful.

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What is partial reflection?

Partial reflection is when only some of the waves are reflected, while other waves are absorbed or transmitted. 

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How can ultrasound waves be used to detect the thicknesses of different mediums within an object?

Ultrasound reflects off of the boundaries between mediums of different densities.


The wave's speed and the time it takes to bounce back to the receiver can be used to calculate the thickness of each medium.

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How can ultrasound waves be used to detect cracks in an object?

The ultrasound would reflect off of the edge of crack and be detected back at the receiver sooner than expected.

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What is sonar?

Sonar is a technique that uses ultrasound waves to navigate, measure distances (ranging), communicate, and detect objects.


It is often used underwater.

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How can sonar be used to calculate the distance between a submarine and the sea floor?

The submarine can emit an ultrasound wave and measure the time it takes to return.


It can then use the speed of the wave and time taken to calculate the distance.

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