Question

Option 1 – How We Hear This activity explores how we hear and how the physical nature of the sound wave determines the quality of the sound experience. Structure of the Ear What are the three main regions of the ear and their associated parts? Briefly describe what happens inside the cochlea? Sound Waves & Frequency What are the three aspects of sound waves? Briefly describe each aspect. Which type of tuning fork would vibrate faster—a small, short one or a large, long one? How is frequency measured and calculated? Explain why longer sound waves lead to lower frequencies and why shorter sound waves lead to higher frequencies. The Theory of Sound Briefly describe the three theories relating to how we perceive pitch. Explain why no single theory can explain human perception of pitch from 20 to 20,000 Hz.

Answer 1

Small/ short objects vibrate faster than similar objects that are larger or longer. The longer produces the top wave & the shortwave produces the bottom waves.

It is measured by counting the number of times the wave goes up & down each second.

When the vibration goes through the middle ear to the cochlea, the oval window moves in & out which causes the pressure in the outer chamber to increase/ decrease in a rapid sequence. Thealternating high/ low pressure in the outer chamber produces ripples in the basilar membrane, & bendsthe hair cells causing them to make neural impulses

Sound waves travel into the ear canal until they reach the eardrum. The eardrum passes the vibrations through the middle ear bones or ossicles into the inner ear. The inner ear is shaped like a snail and is also called the cochlea. Inside the cochlea, there are thousands of tiny hair cells. Hair cells change the vibrations into electrical signals that are sent to the brain through the hearing nerve. The brain tells you that you are hearing a sound and what that sound is.

The ear is divided into three parts:

Outer ear: The outer ear includes an ear canal that is lined with hairs and glands that secrete wax. This part of the ear provides protection and channels sound. The auricle or pinna is the most visible part of the outer ear and what most people are referring to when they use the word “ear.”

Middle ear: Three tiny bones — the malleus, incus, and stapes — within the middle ear transfer sound vibrations from the eardrum to the inner ear. The middle ear is important because it is filled with numerous air spaces, which provide routes for infections to travel. It is also the location of the Eustachian tube, which equalizes the air pressure between the inner and outer surfaces of the tympanic membrane (eardrum).

Inner ear: The inner ear, also called the labyrinth, operates the body’s sense of balance and contains the hearing organ. A bony casing houses a complex system of membranous cells. The inner ear is called the labyrinth because of its complex shape. There are two main sections within the inner ear: the bony labyrinth and the membranous labyrinth. The cochlea, the hearing organ, is located inside the inner ear. The snail-like cochlea is made up of three fluid-filled chambers that spiral around a bony core, which contains a central channel called the cochlear duct. Inside the cochlear duct is the main hearing organ, the spiral-shaped organ of Corti. Hair cells inside the organ of Corti detect sound and send the information through the cochlear nerve.

three aspects of sound waves are:

pressure oscillation waveform===timber loudness amplitude of pressure oscillation pitch frequency of sound waves