The hair movement triggers impulses in nearby nerve cells that form the auditory nerve. These hair cells transduce mechanical energy into neural impulses, similar to the process that happens at the retina in the eye. In the cochlea is the basilar membrane lined with hair cells that are bent by vibrations. Vibrations from the middle ear cause the oval window (cochlea’s membrane) to vibrate, pushing the fluid inside the cochlea. The cochlea is where the physical stimuli of the sound wave is converted into a neural impulse. Right after hitting the eardrum, three bones in the middle ear ( hammer, anvil, stirrup) pick up the vibrations and transmits them to the cochlea. The eardrum is a tight membrane, and when sound waves hit it, it vibrates. Then, a mechanical chain reaction sends the sound waves down through the outer ear to the eardrum.

The pinna channels the sound wave into the ear canal. Your outer ear, which is often called the pinna, is where the process begins. Sound is measured by the amplitude of the sound waves, with decibel (dB) units. This is because of the difference in timbre.

However, even if the same note (pitch) is played on violin and flute at the same volume, you'll notice that they sound different. The shorter the frequency, the higher the pitch. The frequency determines the pitch, which is how high or low a sound is. Each vibration causes molecules to compress and expand the greater the compression, the higher the amplitude, and the louder the sound.Īnother characteristic of a sound wave is frequency, the number of complete wavelengths that pass a certain point in one second. Your sense of hearing is often called audition, but how do we hear sound? It happens when the vibration of sound waves are converted to neural impulses.

Anvil ear also called orricle