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Objective 10/22/2012 Page 42. SWBAT relate waves, particularly sound waves to the noises we hear and why through investigation and video. Jumpstart.

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  1. Objective 10/22/2012 Page 42 SWBAT relate waves, particularly sound waves to the noises we hear and why through investigation and video. Jumpstart Why does your voice sound one way when you hear yourself talking, and “weird” when you hear yourself on a recording/video/voicemail? (Focus on the medium the sound travels through…not anything electronic!) Outro What happens to your hearing if the hairs in your ears die or become paralyzed?

  2. JUMPSTART ANSWERS…. • When you talk normally, the sound waves vibrate the bones of your skull, tendons, and skin, which do not transmit sound waves the same way that air does. • When you talk normally, you hear sound waves vibrating your skull AND passing from air to ears. • When you hear your recorded voice, you only hear sound waves that traveled from the air to the recording device. Since you aren't having your head vibrated, you sound different! YOU are the only one who hears YOU, like YOU do!!

  3. Sound & The Ear NB Page 43 Packet Page 2

  4. Page 2- Why can you hear someone knock on the door when you are on the other side? • When you knock on the door, the particles of the door vibrate. • The vibration creates sound waves that travel through the door. • When the sound waves reach the other side of the door, they make sound waves in the air on the far side.

  5. Hunting with Vibrations- Page 2 Alligator Snake Snakes have no outer ear, but they can hear! They have in inner ear and a functional cochlea. Snakes rest their head on the ground. The lower jaw receives vibrations from an incoming wave. Vibrations transmit directly into the inner ear through bones attached to the lower jaw. • sensitive lip scales enable gator to detect movement and vibration from: • potential prey, • mates, • territorial rivals, • approaching predators

  6. Philosophy vs. Science- Page 2 If a tree falls in the forest and no living creature is there to hear it, does it make a sound? • NO. When a tree falls, the surrounding air (medium) is disturbed, causing sound waves. • When sound waves arrive at our ears they cause small bones in our ears to vibrate. These vibrations then cause nerve impulses to be sent to the brain where they are interpreted as sound. • If there is nobody there to perceive it occurring, then it could not exist as sound, only vibration.

  7. Sound is a longitudinal, (mechanical) wave. • Energy moves in the same direction as the particles move & requires a medium to travel. • Sound waves are often pictured as if they were transverse, because it’s easier to picture.

  8. Humans and Sound Larynx Trachea Vocal chords • voice box at top of trachea; contains the vocal chords • Windpipe • pair of thin tissue in your windpipe; vibrate and allow us to talk and sing

  9. The Ear What three bones are found inside your ear? • Hammer • Anvil • Stirrup hammer anvil stirrup

  10. Page 2- Describe the process in which humans hear from start to finish. • A sound wave is funneled through the outer earinto the middle ear canal. • Sound is amplified by the eardrum which vibrates when the wave hits it (The eardrum stretches across the ear like a drumhead). • The vibrations are transmitted to the three small bones: the hammer, anvil and stirrup. • These bones amplify the vibrations and send the energy to the fluid-filled cochlea in the inner ear. • The vibrations reach hair tipped cells that generate signals containing information (frequency, intensity and duration of the sound). • The stimulations of the tiny hairs send messages to the brain.

  11. Outer ear Human Hearing Middle ear canal Vibrates ear drum Amplified by bones: Hammer, anvil, stirrup Inner ear Hair tipped cells Cochlea converts nerve impulses

  12. Objective 10/22/2012 Page 42 SWBAT relate waves, particularly sound waves to the noises we hear and why through investigation and video. Jumpstart Why does your voice sound one way when you hear yourself talking, and “weird” when you hear yourself on a recording/video/voicemail? (Focus on the medium the sound travels through…not anything electronic!) Outro What happens to your hearing if the hairs in your ears die or become paralyzed?

  13. Outro Answer • You go deaf! • What else might cause hearing loss? • Old age • Higher frequencies are the first to be lost • Distorts sounds you hear • 30% of people over 65 have some hearing loss to aging • Disease/sickness • Mammals cannot make new hair cells • Exposure to loud sounds • Constant exposure can damage hair cells in cochlea

  14. Objective 10/24/2012 Page 44 SWBAT relate the properties of sound to real life experiences through note taking while considering options for their musical instruments project. Jumpstart • What is the order that vibrations pass through the parts of your ear that allows you to hear sounds? • Outer ear  ear canal  ear drum  three bones  cochlea/hair tipped cells  brain Outro What factors can cause you to lose your hearing?

  15. Properties of Sound NB Page 45 Packet Page 3

  16. Properties of Sound: Loudness (pg 3) • Loudness- describes what you actually hear; your perception of the intensity of a sound • Measured in decibels (dB) • Decibel (dB)- unit for measuring loudness of a sound wave • Decibel Scale- measures sound based on human hearing; which makes it one of the most unusual scientific scales • Threshold of hearing: 0 decibels • Threshold of pain: 120 decibels • Larger Amplitude = Louder sound

  17. The Decibel Scale

  18. What is the doctor really doing when she says, “I’m going to listen to your heart”? • The vibrations of the heart, travel to the skin, which create waves which travel up the tubing to the doctor's ears

  19. How does sound cause hearing loss?- Page 3 Amplitude • The louder the sound, and the longer you listen to it, the more hearing you lose! • Intensity- How much energy passes through a given area in an amount of time • Loudness- the perception of how much energy a sound wave carries

  20. Properties of Sound: Intensity- Page 3 • Intensity- amount of energy that a wave carries per second through a unit area • Larger Amplitude = Greater Intensity • Intensity vs. Loudness • Generally, a greater intensity = louder • What is an example of a time when greater intensity does not mean louder? • When the frequency is above the human range of hearing. • If you are far away (distance) from the sound source • Medium is blocking/interfering that sound wave from reaching you (wall, fiberglass)

  21. Properties of Sound: Frequency • Frequency- the number of complete waves that pass a point in one second • Measured in Hertz (Hz) • 1 Hertz is equal to 1 wave per second • 100 Hz is equal to 100 waves per second • Human hearing: 20 Hz - 20,000 Hz Low Frequency High Frequency

  22. Objective 10/24/2012 Page 44 SWBAT relate the properties of sound to real life experiences through note taking while considering options for their musical instruments project. Jumpstart • What is the order that vibrations pass through the parts of your ear that allows you to hear sounds? • Outer ear  ear canal  ear drum  three bones  cochlea/hair tipped cells  brain Outro • What factors can cause you to lose your hearing? • Age, Exposure to loud sounds for long periods of time, Injury/ infection/ sickness, Being born with hearing loss

  23. Objective 10/24/2012 Page 46 SW relate previous properties of sound to new properties and the differences in waves through notes and practice. Jumpstart A boat in distress needs help! It turns on its SOS sound signal, and luckily a plane (in the air 20 °C) and a submarine (under seawater) are within a close distance! The plane and the submarine are each exactly 2 km away. Who will receive the sound signal first? Why? Explain Outro • How could the submarine or the plane change their position in order for the sound to reach them both at the same time?! • The submarine could go deeper underwater, or the plane could fly closer to the boat.

  24. Properties Part 2 NB Page 47 Packet Page 4

  25. Properties of Sound: Pitch (pg 4) • Pitch- description of how high or low the sound seems • Pitch depends on the frequency of the sound wave • Higher pitch = higher frequency = shorter wavelengths • Lower pitch = lower frequency = longer wavelengths • Medical Ultrasound • 1.0 - 20 MHz • Ultrasound • >20,000 Hz • Audible Sound (Human Hearing) • 20Hz-20,000 Hz • Infrasound • 0-20 Hz

  26. Differences in Waves A • This ear-shaped boat moves up and down as the waves arrive—as your eardrum does! • Loudness- Which waves are soft? Loud? • Pitch- Which waves are low? High? B C D

  27. Properties of Sound: • Natural Frequency (def.) – All objects vibrate and oscillate; the frequency at which the particles in an object naturally vibrate; the frequency of the object depends on the speed & wavelength of the object. • Resonance (def.) –The buildup in amplitude of an object when exposed to a sound wave whose frequency is compared to the natural frequency of the object. • If the object is not _______________ (i.e. crystal glass), the object will _______________ (shattering of a glass) • Fundamental Frequency (def.) – the lowestfrequency at which an object will vibrate.

  28. ONLINE Homework- Page 5 • Did You Hear That? • Specifics of Sound

  29. Objective 10/24/2012 Page 44 SWBAT relate the properties of sound to real life experiences through note taking while considering options for their musical instruments project. Jumpstart • What is the order that vibrations pass through the parts of your ear that allows you to hear sounds? • Outer ear  ear canal  ear drum  three bones  cochlea/hair tipped cells  brain Outro • What factors can cause you to lose your hearing? • Age, Exposure to loud sounds for long periods of time, Injury/ infection/ sickness, Being born with hearing loss

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