<h2>Summary</h2>
<ul>
<li>The range of audible frequencies is 20 to 20,000 Hz.</li>
<li>Those sounds above 20,000 Hz are ultrasound, whereas those below 20 Hz are infrasound.</li>
<li>The perception of frequency is pitch.</li>
<li>The perception of intensity is loudness.</li>
<li>Loudness has units of phons.</li>
</ul>
<h2>Glossary</h2>
<h3>loudness</h3>
<p>the perception of sound intensity</p>
<h3>timbre</h3>
<p>number and relative intensity of multiple sound frequencies</p>
<h3>note</h3>
<p>basic unit of music with specific names, combined to generate tunes</p>
<h3>tone</h3>
<p>number and relative intensity of multiple sound frequencies</p>
<h3>phon</h3>
<p>the numerical unit of loudness</p>
<h3>ultrasound</h3>
<p>sounds above 20,000 Hz</p>
<h3>infrasound</h3>
<p>sounds below 20 Hz</p>
<section data-element-type="conceptual-questions"></section>

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Summarizing Hearing

Physics is a science discipline concerned with the nature and properties of matter and energy. Physics topics include mechanics, heat, light and radiation, sound, electricity, magnetism, the structure of atoms, and so on.

Physics

Explore the principles of sound waves and how they affect our ability to hear, including the speed, frequency, intensity, and interference of sounds, as well as the use of ultrasound in medical therapy and diagnostics.


Summarizing Hearing

Summary

Glossary

loudness

timbre

note

tone

phon

ultrasound

infrasound

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