What Are Sound Waves? By Benjamin D. Jackson

            Sound waves are waves of energy that move by transferring energy from one molecule to the next. Sound waves travel outwards in all directions from where they are formed. Sound waves are formed when an object vibrates, this vibration transfers energy to the molecules touching it. Sound waves can travel through: solids, liquids, and gases. However they cannot travel in a vacuum because there are no molecules to transmit the energy.

This is what a sonic boom would look like if we could see sound waves.

Humans use sounds waves as a way to communicate thoughts and ideas. When we speak we are creating sound waves using our vocal cords. Our vocal cords vibrate causing the air molecules in our throat to move , creating sound which travels out of our mouths and into the air to be heard by people nearby. Other animals create sound waves as well, anything you have ever heard is really just a pattern of sound waves hitting your ear.

Speaking of the ear, how does it allow us to hear? The outer ear is the part of the ear that you can see all the time and the ear canal which leads into our heads. The area that most people call the ear collects sound while the canal funnels it to the middle ear. The barrier separating the outer ear from the middle ear is called the Tympanum(eardrum), this is a thin membrane that vibrates and lets the sound waves into the middle ear. The middle ear has three main parts: Stapes(Stirrup), Malleus(Hammer), and Incus(Anvil). These are small bones which act as an energy amplifier, they vibrate and increase the intensity of the sound. The sound then goes into our inner ear or cochlea, where thin hairs feel the vibrations of the molecules of liquid that fill the cochlea. When the hairs vibrate it turns the sound into nerve signals that our brain can interpret.

This diagram shows all of the important parts of the ear.

Despite how cool sound waves are and how interesting the ear is, what I find most interesting about sound is how animals use it. Animals that use echolocation, emit a high pitched sound and then wait for it to bounce back to their ears. When they hear the sound waves from their sound they are able to discern what objects looked like, their size and how far away they are. Many types of bats and a few types of birds use this as a way to hunt and to maneuver around any obstacles in their path. Sonar is what it is called when a marine mammal uses echolocation while underwater. Whales, dolphins, and many other types of marine life use sonar every day.

My parting question to you is, what is the greatest possible measure of decibels?