Human Ear

It has been discovered that sound is a type of energy. Vibrations cause it to happen. Longitudinal waves are sound waves. Because they are elastic waves, they must be transmitted through a material medium. They can move through solids, liquids, and gases. In solids, their velocity is greatest, whereas, in gases, it is lowest. 

In our daily lives, we hear a variety of sounds, including pleasant ones known as musical sounds, noise, loud sound, high-pitched sound, and other unpleasant sounds are examples. The majority of mammals on Earth have an external ear. Our auditory system includes the ear. The pinna is the part of the ear that is visible from the outside. Humans, like other mammals, have ears. The temporal bones of the skull house the ears on both sides of the brain. Before discussing the human ear and its range of hearing first we’ll discuss the production of sound and sound waves.

Production of Sound

Objects vibrate, which causes the sound to be created. The quick to and fro motion of an object is known as vibration. All noises originate from vibrating objects. Noise is created by irregular, chaotic vibrations. Music can be created through regular, regulated vibration. All sound is made up of pure frequency combinations. When a stretched rubber band is plucked, it vibrates and makes a sound.

Sound Wave as a Mechanical Wave

When a vibrating object goes ahead, it compresses and pushes the air in front of it, creating a high-pressure zone known as compression (C). When a vibrating object goes backward, it creates a low-pressure zone known as rarefaction (R). A vibrating item that causes compression (C) and rarefaction (R) .The particles in these waves move back and forth parallel to the disturbance’s propagation path, Longitudinal waves are the name for these types of waves. Another type of wave is known as transverse waves, the particles oscillate up and down perpendicular to the propagation of the disturbance direction in these waves. In a medium, sound propagates as a succession of compressions (C) and uncommon fractions (R). The higher component of the curve, known as the crest, represents compressions, which are places of high pressure and density where the particles are crowded. Rarefactions are low-pressure, low-density areas where particles are dispersed, and they are represented by the trough portion of the curve.

Sound Frequency

• The frequency of a sound wave is defined as the number of oscillations per unit time.
• The SI unit for it is hertz (Hz)

Human Ear

The ear is a human organ that allows us to hear sounds in our environment. The primary function of the ear is to keep us balanced and to distinguish different noises. It aids in the conversion of pressure fluctuations into electronic impulses that flow through the auditory nerve to the brain.

Human Ear is mainly divided into three parts as:

1. Outer Ear
2. Middle Ear
3. Inner Ear

Outer Ear

Sound waves pass over the outer ear whenever they enter our ear. The ear translates audible frequencies into electrical signals, which are then transmitted to the brain. Pinna and earlobe are the large parts of the outer ear with a shell-like structure. The compressions that reach the outer ear, i.e. the pinna, are directed to the canal and eventually reach the eardrum or membrane. The inner ear and outer ear are separated by a flexible membrane. These compressions are magnified by the three bones inside the ear multiple times.

Middle Ear

Bones are found in the center of the body and are connected to one another. The three bones that convey sound are the hammer, anvil, and stirrup. The hammer is attached to the middle of the eardrum. The sound of the hammer vibrating is transmitted to the other two bones, the anvil and stirrup. The sound waves are amplified by these bones, which are located in the middle ear. So, what does the outer ear do? It draws in sound waves, which are then amplified by the inner ear.

Inner Ear

The Cochlea, or inner ear, is a snail-like structure. Because there is some fluid inside the cochlea, when the number of variations is conveyed in the middle ear, the cochlea sends the sound to the brain. The auditory nerve receives these electrical impulses. 

Human Ear

Function of the Human Ear

The human ear’s various structures aid in various purposes.

• The eardrum is protected by the pinna of the outer ear, which transports sound to the eardrum through the auditory canal.
• When the eardrum vibrates, sound is transmitted to the inner ear.
• The middle ear’s ossicles enhance sound and transmit vibrations to the oval window. The membrane that separates the inner and middle ear is known as the oval window.
• The Eustachian tube is a thin tube that links our nose to our ear. This tube aids in the passage of air into the lungs and discharges mucus to the nasopharynx.
• The cochlea is a structure found in the inner ear. It is filled with fluid and houses the Corti organ. Cortis organ has cilia, which are hair-like sensory cells. Waves from the middle of the year generate vibrations in the inner ear fluid, which causes the cilia to vibrate. The cilia vibrates, sending nerve signals to the brain.
• The semicircular canals in the inner ear are vertically aligned with one another. It also has fluid in it, which aids in mobility.

Range of Hearing of Human

• The audible range of sound is defined as the range of frequencies that humans can hear between 20 Hz and 2000 Hz.
• Infrasonic sound is defined as sound with a frequency less than 20 Hz.
• Ultrasonic sound is defined as sound with a frequency greater than 2000 Hz.

Humans cannot hear both infrasonic sound and ultrasonic sound

Read More,

• How do we hear?
• Audible and Inaudible Sounds

Sample Question

Question 1. How many different types of hearing loss have you seen in people?

Answer:

There are three types of hearing loss as

1. Conductive hearing loss: Sound cannot be transmitted from the outer to the inner ear with this type of hearing loss. This can be caused by an ear infection, ear trauma, or a buildup of ear wax.
2. Sensorineural hearing loss: Either the cochlea or the hearing nerves are affected in this form of hearing loss. This can occur as a result of advanced age, noise exposure, or cancer therapy.
3. Mixed hearing loss: The combination of conductive and sensorineural hearing loss causes this form of hearing loss. This can happen for a variety of reasons, including the causes of both hearing loss and hearing loss.

Question 2. Is it possible to hear a cell phone ringing in a vacuum chamber?

Answer:

When a bell vibrates in air, air molecules are pushed out of the way, causing the vibrations to “decay.” If you ring a bell in a vacuum, the loss mechanism isn’t present, hence the bell will “rang” for a longer time (but nobody can hear it). This does not imply that the initial amplitude is considerably higher; it just means that it lasts longer.

Question 3. Write functions of human ear.

Answer:

The human ear’s various structures aid in various purposes.

• The eardrum is protected by the pinna of the outer ear, which transports sound to the eardrum through the auditory canal.
• When the eardrum vibrates, sound is transmitted to the inner ear.
• The middle ear’s ossicles enhance sound and transmit vibrations to the oval window. The membrane that separates the inner and middle ear is known as the oval window.
• The Eustachian tube is a thin tube that links our nose to our ear. This tube aids in the passage of air into the lungs and discharges mucus to the nasopharynx.
• The cochlea is a structure found in the inner ear. It is filled with fluid and houses the Corti organ. Cortis organ has cilia, which are hair-like sensory cells. Waves from the middle of the year generate vibrations in the inner ear fluid, which causes the cilia to vibrate. The cilia vibrates, sending nerve signals to the brain.
• The semicircular canals in the inner ear are vertically aligned with one another. It also has fluid in it, which aids in mobility.

Question 4. What is the range of hearing in humans?

Answer:

The audible range of sound is defined as the range of frequencies that humans can hear between 20 Hz and 2000 Hz. Infrasonic sound is defined as sound with a frequency less than 20 Hz. Ultrasonic sound is defined as sound with a frequency greater than 2000 Hz. But humans cannot hear both infrasonic sound and ultrasonic sound

Question 5. What is the mechanism through which bats use ultrasound to catch their prey?

Answer:

Ultrasounds are sounds with frequencies more than 20000 Hz. Ultrasound is used by bats to navigate (move) and catch prey. Bats make ultrasonic squeaks with a high frequency. These squeaks reverberate off prey and then return to the bat’s ears. This provides bats with a sense of prey location, allowing them to catch the prey.

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Article Tags :

• Class 9
• School Learning
• School Physics
• Physics-Class-9