How We Hear

Do dogs and cats have better hearing than people? Join Proton the cat as he tests the Professor's latest invention, goggles that allow us to SEE sound waves. Take an auditory tour of the lab and learn sound that cannot be duplicated in classroom materials. Read More

This game requires JavaScript and Flash.

If you’ve ever wondered how we hear sound, it all starts with vibrations in the air then transmission to the ear, and ends with electrical impulses to the brain. Your ears’ pick up the sounds around you and translates them into information your brain can understand. The science of sound is a remarkable process that is completely mechanical; your hearing is based solely on physical movement.

All objects produce a sound when it vibrates. Usually, we hear sounds travelling through the air. When something vibrates in the air, it moves the particles around it. Those particles move the air particles around them, carrying the vibration pulse through the air. When the particles are colliding with other particles in front of them it is called compression. As the particles move out it creates a drop in pressure called rarefaction.

A vibrating object sends a wave of pressure fluctuation through the air. We hear different sounds from different vibrating objects because of variations in the frequency, or sound wave. If the vibration wave switches back and forth quickly produces a higher wave frequency. We hear this as a higher pitch. If there are fewer switches back and forth in the frequency this a lower pitch. The level of air pressure in each switch back and forth is the wave’s amplitude, which determines how loud a sound is. 

The ear is able to capture these sound waves by sensing the fluctuations in the air pressure, directing the sound into the eardrum and translating these fluctuations into signals that your brain can understand. The outer part of the ear called the pinna, serves to catch the sound waves. The outer ear has a number of curves, which help determine the direction of sound.  The sound waves proceed to travel down the ear canal and interact with the eardrum. They vibrate the tympanic membrane of the eardrum; the compressions and rarefactions of sound waves push the drum back and forth. High-pitch sound waves move the drum rapidly, and louder sound moves the drum a greater distance. The eardrum helps translate these sound waves into electrical impulses, which the brain can understand.

Do dogs and cats have better hearing than people? Join Proton the cat as he tests the Professor's latest invention, goggles that allow us to SEE sound waves. Take an auditory tour of the lab and learn sound that cannot be duplicated in classroom materials.