Making Human Sounds

• When you speak or sing, you push air from your lungs past your vocal cords, which are two flaps of tissue inside your throat. When you tighten your vocal cords, you can make the sound have a higher pitch. Do this lab to explore how you change the shape of your throat to vary the pitch of sound.

Making Human Sounds

1. Hold your fingers against the front of your throat and say Aaaah. Notice the vibration against your fingers.

2. Now vary the pitch of this sound from low to high and back again. How do the vibrations in your throat change? Record your observations on page 110.

Making Human Sounds

3. Change the sound to an Ooooh. What do you notice as you listen? Record your observations.

4. Think critically In your science notebook on page 110 describe how the shape of your throat changed the pitch.

Sound

What do you hear?• Did you hear something? Maybe the

sound you heard was as quiet as your cat licking her paws. Or maybe it was loud, like a siren going by.

• Sounds are everywhere, and you have two cool parts on your body that let you hear them all: your ears!

• No matter where we go, sound waves are all around us.

SoundsClose your eyes and listen to these sounds.

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Sound• Question: What is sound?

–A vibration that produces a wave.

–http://teachertube.com229809

Sound• A wave carries energy from one place to

another without transferring matter.

• An object that is vibrating in air, such as your vocal cords or a ear bud speaker produces a sound wave.

Sound

Sound• Epiglottis: Flap of skin that covers the

larynx during swallowing, preventing food from entering the trachea.

• Trachea: windpipe that carries oxygen to the lungs and carbon dioxide out.

• Larynx: Upper part of the respiratory system that holds the vocal cords.

• Vocal Cords: Vibrate during speech to produce sounds.

• Fire Video http://www.youtube.com/watch?v=93DFanOXzL8

Sound• The vibrating object causes air

molecules to move back and forth. As these molecules collide with those nearby, they cause other air molecules to move back and forth. In this way, energy is transferred from one place to another. This is done just as the slinky moves back and forth.

Sound• Question: Can you experience sound

waves by feeling vibrations?– When the bass is turned up high.

Sound• Question: Does sound travel faster in air

or through a solid material?– Recall that as sound waves travel through a

material, the particles collide with each other.

• Question: Are particles of a material closer together in a solid or a gas like air?– In a solid particles are closer together than in

liquids or gases.– Therefore speed of sound is fastest in solids.

Sound• Sound waves are mechanical waves,

which means they need a medium to travel through and they can’t travel through a vacuum.

• It is the sound energy that travels through a medium not the particles of the medium.

• The particles of the medium move back and forth as the sound wave passes, but then return to their original positions.

Sound

Sound• What is SONAR?

• Sound Navigation And Ranging.– Uses sound to detect objects under the

surface of the water. Videos: Submarines and Sonar 2, Dolphins Sonar

1:30

Sound• Question: What is the difference between

loud sounds and quiet sounds?

• What is the difference between playing a song at a high volume versus a low volume?– Loud sounds carry more energy than soft

sounds.

Sound• Loudness is the human perception

of how much energy a sound wave carries.

Sound• Decibel Scale: Measure of the

energy carried by sound

waves.

Sound• Dangerous levels of sound energy.• You must learn to protect your hearing or you

may have hearing problems later in life. • Have you ever had ringing in your ears?

Sound• Pitch: How high or low a sound is.

Pitch corresponds to frequency. The higher the pitch the higher the frequency.

• Question: Name a musical instrument with a high pitch.

• Question: Name a musical instrument with a low pitch.

Sound• Pitch: Humans can detect frequencies

between about 20Hz and 20,000Hz.

• Dogs can detect up to 50,000Hz.

• Bats as high as 150,000Hz.

Sound• Echo: A reflected sound wave

Sound• Echolocation: Emitting high

pitched squeaks and listening for echoes to determine location.

• Bats and dolphins use echolocation to navigate.

• Video: Echoes and

Echolocation 1:29

Sound• Sound waves can be used to treat certain

medical problems.1. Small incision is made in the eye, then an ultrasonic instrument

uses sound waves to break up the lens, and the particles are removed.

2. Breaking up kidney stones.Video: Ultrasound 2:44

Music• Music: A group of sounds

deliberately produced to make a regular pattern.

• The difference between music and noise can vary from person to person.

• Music is created by vibrations.– You beat a drum, the head vibrates. You play

a guitar the string vibrates. You tap a bell, it vibrates at a certain frequency.

Music• Natural frequencies: Every object

will vibrate at a certain frequency.

Music• Question: How can someone singing at a

loud high note cause glass to shatter?– Sometimes sound waves can cause an object

to vibrate.– Scientific American article.– Video: Shattering Glass

• 5:18

Music• Resonance: An object is made to vibrate

at its natural frequency by absorbing energy from a sound wave.– The vibrating tuning fork causes the table to

vibrate at the same frequency, or resonate. The combined vibrations of the table and tuning fork increase the

loudness of the sound

waves produced.

Music• Question: Before a concert what do all the

musicians do?– Tune their instruments by playing the same

note.

Music• Most musical instruments produce

more than one frequency at which they vibrate.

• Fundamental frequency: The lowest frequency produced by a vibrating object.

• Overtones: Higher frequencies produced by a vibrating object.

Music• Reverberation: Repeated echoes

of sound. – In a empty gym the sound of your voice can

be reflected back and forth several times by the floor, walls, and ceiling.

– Video: Reverberation 2:15

Comparing and Contrasting Sounds Activity

• Strike a block of wood with a spoon and listen carefully to the sound. Then press the block of wood to your ear and strike it with the spoon again. Listen carefully to the sound.

• Tie the middle of a length of string to a metal spoon. Strike the spoon to hear it ring. Now press the ends of the string against your ears and repeat the experiment. What do you hear? Record your observations.

Comparing and Contrasting Sounds Activity

• Data and Observations: Sound

1.Wood:

2.Wood against ear:

3.Metal spoon:

4.String against ear:

Comparing and Contrasting Sounds Activity

• Analysis:

1.Did you hear sounds transmitted through wood and through string? Describe the sounds.

2.Compare and Contrast the sounds in wood and in air.

Ear

• Definitions:

anvil - (also called the incus) a tiny bone that passes vibrations from the hammer to the stirrup.cochlea - a spiral-shaped, fluid-filled inner ear structure; it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form.eardrum - (also called the tympanic membrane) a thin membrane that vibrates when sound waves reach it.Eustachian tube - a tube that connects the middle ear to the back of the nose; it equalizes the pressure between the middle ear and the air outside. When you "pop" your ears as you change altitude (going up a mountain or in an airplane), you are equalizing the air pressure in your middle ear.hammer - (also called the malleus) a tiny bone that passes vibrations from the eardrum to the anvil.nerves - these carry electro-chemical signals from the inner ear (the cochlea) to the brain.outer ear canal - the tube through which sound travels to the eardrum.pinna - (also called the auricle) the visible part of the outer ear. It collects sound and directs it into the outer ear canalsemicircular canals - three loops of fluid-filled tubes that are attached to the cochlea in the inner ear. They help us maintain our sense of balance.stirrup - (also called the stapes) a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the smallest bone in the human body (it is 0.25 to 0.33 cm long).

Ear• Outer Ear: Collects sound waves

and directs them into the ear canal.

Ear• Middle Ear: Sound waves vibrate the

eardrum, which is a membrane that stretches across the ear canal. When the eardrum vibrates, it transmits vibrations to three small bones which amplify the sound

Ear• One of the three small bones vibrates

another membrane leading into the inner ear, which is filled with fluid. Vibrations in the fluid are transmitted to hair-tipped cells. These cells generate signals containing information about sounds. The nerve impulses from the cells then travel to the brain.

• Video: Ear 1

• Worksheet.

Cochlear Implants

• Brain Pop “Hearing”

• Little Girl Hearing for the First Time BmU2JSZzpLI

• Baby ZDD7Ohs5tAk