Sound Waves & Hearing

How do we Hear Sounds??

Essential Standard

• 6.P.1Understand the properties of waves and the wavelike property of energy in earthquakes, light and sound waves.

Clarifying Objective

• 6.P .1.3Explain the relationship among the rate of vibration, the medium through which vibrations travel, sound and hearing.

Essential Questions

• How does sound travel through the mediums of solids, liquids, & gasses?

• How is the human ear designed to receive sound waves?

• How do vocal chords work to produce sound?

EOG Questions

• What is the relationship between the speed of sound and the medium through which it passes?

• If a guitar player adds thicker strings how will it effect the vibrations of the strings?

Waves• Waves are a disturbance or

vibration a way of transferring ENERGY from one place to another

• They transport ENERGY from on place to another

• There are different categories & types of waves

• They all have their own characteristics that make them waves

What is Sound• Sound is vibrations of energy that

travel through a medium and can be heard and processed by human or animal ears

• Vibrations

• Travel through a medium– Solid – Liquid– Gas

• Heard and processed by humans or animals

• http://www.youtube.com/watch?v=czr7122MBOY

Mechanical Waves

• Mechanical Waves are waves that require a solid, liquid or gas to move through

① Transversal Waves

② Longitudal Waves

Longitudinal Waves

• Longitudinal Waves are like pinball waves. These waves vibrate in the direction of the flow of energy

• An example is a pinball machine

• http://www.youtube.com/watch?v=yd-G6KYwzvA

• 2:48-3:47

How is Sound Created

① Sound Starts when an object is vibrated

• The vibrations send out energy in a Longitudinal wave through a medium

• The energy travels through either liquids, solids, or gases

Traveling through Mediums

• Sound waves are mechanical waves meaning they must travel through a medium (unlike Electromagnetic Waves)

• Solid• Liquid • Gas

Traveling Sound• Sound travels fastest through

solids

• It travels at a medium speed through liquids

• Sound travels slowest through gases

• http://www.youtube.com/watch?v=_pcsOG-H3Ac

• 2:53-3:40

Essential Questions

• Get with a partner and answer…

• How does sound travel through the mediums of solids, liquids, & gasses?

Particles Vibrating

② Next particles (atoms) crash into each other sending a chain reactions to the next particle & so on

• http://www.youtube.com/watch?v=ACeUO4ufx2I

Atoms/Energy Hits the Ear

③ The particles of atoms/energy crash into each other until they hit the human ear

④ The outer ear catches these atoms/energy and helps us determine…

Direction Frequency

Hitting the Ear Drum

• The sound waves then travel down the ear canal and hit the ear drum

• The ear drum begins to vibrate from the repeated atoms/energy hitting it

Milieus • The vibrating ear drum then

hits the first of three very small bones in the inner ear (smallest bones in the body)

• This bone is called the Milieus which is attached to the ear drum

• It is attached to the next bone and sends the vibration through

Incus

• The vibration then hits the Incus

• The Incus is the middle bone in the inner ear

• The Incus transfers the vibration of energy to the last of the 3 inner ear bones

Stapes

• The sound vibration is then sent to the last of the inner ear bones called the Stapes

• The Stapes hits the side/wall of the cochlea and sends sound waves

Cochlea • Inside the Cochlea there are

about 20,000-30,000 little fibers that are kind of like blades of grass

• These fibers are set to only recognize certain frequencies

• When the specific frequency hits the specific fiber it sends a signal to tiny hair cells

Cochlea

• The tiny hair cells take the specific frequency to the Cochlear nerve

• The Cochlear nerve then sends that frequency to the brain

• The Brain identifies the sound and puts a name to the sound

How we Hear

• http://www.youtube.com/watch?v=_pcsOG-H3Ac

• 8:32-9:00

• http://www.youtube.com/watch?v=qgdqp-oPb1Q

Essential Questions

• Get with a partner and answer…

• How is the human ear designed to receive sound waves?