swrs: What is sound? – Measuring sound

What is sound? 

As humans we have 5 defined senses. These senses are the means by which we take in the environment around us. They are sight, sound, taste, smell, and touch. We will be dealing with sound.

Sound is created when something in the environment causes vibrations to travel through the air. If someone were to bang 2 rocks together, if a bird chirped, if a car drove by, if somebody plucked a guitar string… all of these things create vibrations that move through the air. People and other animals hear that as sound. Hearing is essentially one of the means by which animals take in their surroundings.

*sound also travels through other mediums such as water, where it sounds much different.

Human beings at their best are capable of hearing sounds ranging from 20 Hz to 20 kHz (20 hertz to 20 kilohertz). Hertz and kilohertz are the measurement used to identify the rate or *frequency of vibration per second. Our hearing begins at vibrations of 20 times per second (20Hz), and ends at 20,000 times per second (20kHz).

Lower vibrations per second produces a bassier sound, and higher vibrations per second produces a higher pitch sound. Lower frequency/higher frequency.

When it comes to “volume” or perceived loudness, we use dB (decibels) as a unit of measurement. Decibels, however, can be a difficult concept to nail down because we as humans do not have a benchmark for what it would be to hear nothing. Even in total sound deprivation we would still be hearing our own bodies working. Because of this 0dB is often referred to as the threshold for healthy hearing.

Relative dB examples would include a pin drop measuring in at 10 dB, a toilet flushing at 75 dB, a motorcycle at 100 dB, or a shotgun measuring at 160 dB.


This video will help you understand the basics of sound and how it applies to our lives.