Mr' Perez

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Mr. Perez

• Grade 6 Science
• How Do We Hear?

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Hearing Sounds

• Hearing is one of the FIVE human senses
• For a sound to be heard, three things are needed
• A source of the sound (like your voice, an
  instrument, a cannon fired, a car engine racing,
  a plane flying overhead, a splash of water, etc.)
• A medium to transmit the sound (gas, liquid, or
  solid)
• The human ear (which is a sense organ that
  detects the sound and transmits electrical
  impulses to the brain)

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The Human Ear

• There are THREE main parts to the human ear
• The outer ear
• The middle ear
• The inner ear

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The Outer Ear

• A sound wave first enters the outer ear
• The part of the ear that we can see is called the
  pinnacle
• The outer ear funnels the sound wave into the ear
  canal
• The sound wave moves through the ear canal to the
  eardrum
• The vibrating air particles in the sound wave
  make the eardrum vibrate

• These vibrations are sent to the middle ear

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The Middle Ear

• The vibrations from the eardrum are transferred
  to the bones in the middle ear
• The three tiny bones in the middle ear are called
  the hammer, anvil, and stirrup
• The vibrations are sent from the hammer, to the
  anvil, to the stirrup

• These vibrations are sent to the inner ear

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The Inner Ear

• The vibrations from the tiny bones in the middle
  ear are received by the cochlea (which is
  snail-shaped)
• The cochlea is filled with fluid and is attached
  to nerve fibers
• The vibrations from the cochlea become nerve
  impulses, which are sent to the brain by the
  auditory nerve

• The cochlea converts mechanical energy to
  electrical impulses
• The brain interprets the electrical impulses as
  sound

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The Ear and Balance

• The semicircular canals of the inner ear contain
  fluid
• When we move, the fluid in the semicircular
  canals moves too
• This lets us know our position and helps us to
  keep our balance

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The Ear and Pressure

• The Eustachian tube connects the middle ear with
  the back of the mouth
• When your ear pops, that is the Eustachian tube
  working to keep the air pressure on both sides of
  the eardrum equal

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Hearing Loss

• Hearing loss can occur when your inner ear or
  auditory nerve is damaged
• Young children often experience a build up of
  water in the inner ear, which creates an
  infection (and could include temporary or
  permanent hearing loss)
• Earwax build-up, fluid, or a punctured eardrum
  can prevent sound waves from reaching your inner
  ear
• Possible treatments for hearing loss include
  hearing aids, assistive listening devices,
  alerting devices, special training, certain
  medicines, and surgery