Sound is a Wave Pages 37-43 (section C)

Sound is a Type of Mechanical Wave

• Sound - a wave that is produced by a vibrating object and travels through matter

• Vibration - a rapid, back and forth motion

How Sound Waves are Produced in the Human Body

• Your muscles push air up from you lungs and through the narrow opening between the vocal cords.

• The force of the air causes the vocal cords to vibrate.

• The vibrating vocal cords produce sound waves

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How Sound Waves are Detected by the Human Body

• Outer ear collects sound waves and reflects them into the ear canal.

• The ear drum ( at the end of the ear canal) vibrates

• The middle ear contains 3 tiny, connected bones (hammer, anvil stirrup) The bones carry vibrations to the inner ear.

• The cochlea sends the vibrations to the brain

Cochlea

• The cochlea has about 30,000 hair cells.

• These hairs can be easily damaged, causing hearing loss.

Sound Waves Vibrate Particles

• Sound waves travel by compression.

• The particles in the medium (usually the air) are compressed and transfer the energy as sound.

Sound Waves are Mechanical Waves

• Since sound waves are mechanical waves they require a medium to travel through.

• A vacuum is empty space. Sound can not travel in a vacuum.

Speed of Sound

• Sound travels more slowly than light.

• Sound does not always travel at the same speed.

• Sound travels faster in liquids than in gases.

• Sound travels faster in higher temperatures than lower temperatures.

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