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Space Travel and Exploration
Science Experiments
Sound Waves

What is the speed of ultrasound waves in the air?


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March 16, 2013 7:32PM

The 'normal' speed of sound is 340 m/s in dry air at room temperature and pressure.

From your question, it appears we should differentiate the terms "ultrasonic" and "supersonic".

Ultrasonic relates to sonic frequencies higher than 20 KHz, i.e. beyond audible range. For a given gas, the speed of sound is independent of the frequency of the sound measured and also independent of the density of the gas.

Supersonic relates to a speed of an object greater than the normal speed of sound (340 m/s in air at STP) and usually the phenomena associated with it.

The speed of sound is also a functionof the medium through which it's passing. For example, the speed of sound through water is 1,500 m/s, and is slightly over 5,000 m/s in iron.

So to answer your question, the speed of ultrasound in airis340 m/s for the reasons given.