Chapter Menu Lesson 1: Sound Lesson 2: The Ear and Hearing Click on a hyperlink to view the corresponding lesson.

12.1 Sound compression wave loudness amplitude decibel scale pitch

What is sound? Vibrations make all sounds. All sounds are transmitted by waves.

12.1 Sound Sound Waves When you speak, the vocal cords move the air in your throat, and the vibrations continue as a wave through the air. The energy that moves one molecule of air is passed on to the next one. Energy is transferred from one place to another.

12.1 Sound Sound Waves (cont.) In a compression wave, particles move back and forth in the same direction the sound wave moves.

12.1 Sound Sound Waves (cont.) The wavelength is the distance between the centers of two regions of compression, or two regions of rarefaction. The frequency is the number of wavelengths that pass a certain point in one second, measured in hertz (Hz).

12.1 Sound Vibration When an object vibrates, it puts pressure on the surrounding molecules. The compressions and rarefactions move away from the speaker in all directions, creating a sound wave.

12.1 Sound Playing in Tune When you play middle C on a properly tuned violin, the string vibrates in a certain pattern that makes the note. The vibration of the string is too complex to produce just one note at a time. It also produces vibrations that matches and blends with middle C, creating a rich sound.

Amplitude and Loudness 12.1 Sound Amplitude and Loudness Loud sound waves generally carry more energy than soft sound waves. Because of the structure of the ear, not all sound waves with the same energy have the same loudness. Loudness—measured in phons—is a person’s perception of how much energy a sound wave carries.

Amplitude and Loudness (cont.) 12.1 Sound Amplitude and Loudness (cont.) The amount of energy a wave carries depends on its amplitude. Sound waves with greater amplitudes carry more energy and sound louder.

12.1 Sound The Decibel Scale Your perception of the amount of energy in a sound wave is measured on the decibel scale. Damage to a person’s hearing can begin with sounds of about 85 dB.

12.1 Sound Frequency and Pitch Pitch—how high or how low a sound is—corresponds to frequency The higher the pitch, the higher the frequency is. The human ear can detect sound waves with frequencies between 64–23,000 Hz. Some animals can hear sounds with even higher or lower frequencies.

12.1 Sound How does human hearing compare with that of other animals’? Range of Hearing

Which does not describe a compression wave? 12.1 Sound A B C D Which does not describe a compression wave? A areas of molecules with high density and pressure B areas of molecules with low density and pressure C sound wave D low frequency Lesson 1 Review

What does a wave’s amplitude depend on? 12.1 Sound A B C D What does a wave’s amplitude depend on? A how many decibels it measures B frequency C how spread out the areas of compression and rarefaction are D the frequency and power put into the wave Lesson 1 Review

When can hearing damage begin to occur in humans? A 23,000 Hz 12.1 Sound A B C D When can hearing damage begin to occur in humans? A 23,000 Hz B 1,000 Hz C 110 dB D 85 dB Lesson 1 Review

End of Lesson 1

12.2 The Ear and Hearing external ear auditory canal tympanic membrane malleus incus stapes cochlea echo

Functions of the Ear The outer part of your ear collects sound waves. 12.2 The Ear and Hearing Functions of the Ear The outer part of your ear collects sound waves. Your middle ear passes the sound waves to your inner ear, which processes the waves into electrical impulses.

12.2 The Ear and Hearing Structures of the Ear The human ear is made up of three parts: the outer ear, the middle ear, and the inner ear.

Structures of the Ear (cont.)

12.2 The Ear and Hearing The Outer Ear The external ear is made up of folds of cartilage and skin. The auditory canal is the part of your ear that collects sound waves from the external ear and passes them to the middle ear.

12.2 The Ear and Hearing The Middle Ear The vibrations of the tympanic membrane—more commonly called the eardrum—cause three tiny bones to transmit sound waves to the inner ear. Two small muscles control the tension on the eardrum and the bones of the middle ear.

12.2 The Ear and Hearing The Middle Ear (cont.) The malleus, the incus, and the stapes rest in a fluid-filled vessel called the eustachian tube. The eustachian tube connects the middle ear to the throat. When you swallow, the pressure is adjusted in your eustachian tube and middle ear.

12.2 The Ear and Hearing The Inner Ear The twists and turns found in the inner ear allow many sensory cells to be packed into a small space.

12.2 The Ear and Hearing The Inner Ear (cont.) An oval window passes the vibration on to the fluid in the cochlea. The cochlea is lined with sensory cells.

12.2 The Ear and Hearing Hearing in Humans When a sound wave hits the tympanic membrane, it causes a vibration which is passed to the tiny bones in your inner ear. The vibration of the fluid in the cochlea bends the hairs in the sensory cells, which sends a signal to the brain. The further a hair is deflected, the louder the brain recognizes the sound to be.

Hearing Damage Hearing damage can occur in almost any part of the ear. 12.2 The Ear and Hearing Hearing Damage Hearing damage can occur in almost any part of the ear. If something prevents sound from being transmitted through the outer and middle ear, conductive hearing loss occurs.

Effect on Ear Structures 12.2 The Ear and Hearing Effect on Ear Structures Colds or allergies can cause temporary buildup of fluid in the middle ear. Aging or exposure to loud noises can cause damage to the cochlea.

Correcting Hearing Damage 12.2 The Ear and Hearing Correcting Hearing Damage If fluid has accumulated in the middle ear, medicines can treat the infection and hearing may return to normal. Sensorineural hearing loss is permanent and can be corrected only with hearing aids or other devices.

Hearing in Other Mammals 12.2 The Ear and Hearing Hearing in Other Mammals Some mammals use a system for hearing that is similar to the human hearing system. Some mammals posses qualities that allow them to hear certain sounds better than humans can. Redirecting sound helps some animals determine the direction from which the sound is coming.

Echolocation An echo is a reflected sound wave. 12.2 The Ear and Hearing Echolocation An echo is a reflected sound wave. The amount of time it takes an echo to bounce back depends on how far away the reflecting surface is.

What is the function of the external ear? A collect sound waves 12.2 The Ear and Hearing A B C D What is the function of the external ear? A collect sound waves B transfer sound waves to the inner ear C transfer sounds waves to the outer ear D protect the inner ear Lesson 2 Review

What do vibrations in your eardrum cause to occur next? 12.2 The Ear and Hearing A B C D What do vibrations in your eardrum cause to occur next? A send a signal to the brain B bend the hairs in the cochlea C move the bones of the middle ear D move fluid in the cochlea Lesson 2 Review

C the hairs in the cochlea D oval window 12.2 The Ear and Hearing A B C D What passes vibrations from the tympanic membrane onto the fluid in the cochlea? A eustachian tube B malleus C the hairs in the cochlea D oval window Lesson 2 Review

End of Lesson 2

Chapter Resources Menu Chapter Assessment California Standards Practice Concepts in Motion Image Bank Science Online Virtual Lab Click on a hyperlink to view the corresponding feature.

What makes all sounds? A waves B vibrations C compression D rarefaction Chapter Assessment 1

What does not play a role in measuring loudness with phons? B C D What does not play a role in measuring loudness with phons? A a reference frequency B power C dB D frequency Chapter Assessment 2

What is pitch? A amplitude B wavelength C loudness D frequency A B C D Chapter Assessment 3

The auditory canal is located in the ____. A outer ear B middle ear C inner ear D cochlea Chapter Assessment 4

Where do the malleus, incus, and stapes rest? A outer ear B inner ear C middle ear D oval window Chapter Assessment 5

Which property of waves is not related to how much energy they carry? SCI 5.g A B C D Which property of waves is not related to how much energy they carry? A loudness B pitch C dB D amplitude CA Standards Practice 1

Which property of a sound wave changes as its energy changes? SCI 5.g A B C D Which property of a sound wave changes as its energy changes? A frequency B pitch C wavelength D amplitude CA Standards Practice 2

Which is not a bone in the middle ear? A malleus B cochlea C stapes SCI 5.g A B C D Which is not a bone in the middle ear? A malleus B cochlea C stapes D incus CA Standards Practice 3

If a sound has a low pitch, what else is always low? A frequency B dB SCI 5.g A B C D If a sound has a low pitch, what else is always low? A frequency B dB C amplitude D wavelength CA Standards Practice 4

Which part of the ear is like a labyrinth? A outer ear B inner ear SCI 5.g A B C D Which part of the ear is like a labyrinth? A outer ear B inner ear C middle ear D auditory canal CA Standards Practice 5

Concepts in Motion 1

Image Bank

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