# Sound How does sound work Sound What is

• Slides: 34

Sound How does sound work?

Sound: What is it? l Sound is a disturbance that travels through a medium as a longitudinal wave.

Interactions of sound waves: l Reflection: Sound waves reflect when they strike an object.

Interactions of sound waves: l Reflection: Sound waves reflect when they strike an object. l You hear this as an echo.

Interactions of sound waves: l Reflection: Sound waves reflect when they strike an object. l You hear this as an echo. l Diffraction: Sound waves “bend” around corners or “squeeze” through a door.

Interactions of sound waves: l Reflection: Sound waves reflect when they strike an object. l You l l hear this as an echo. Diffraction: Sound waves “bend” around corners or “squeeze” through a door. Interference: Sound waves may interact with each other.

Speed of sound waves: l Depends on the elasticity, density, and temperature of the medium the sound is traveling through.

Speed of sound waves: l Depends on the elasticity, density, and temperature of the medium the sound is traveling through. l Elasticity: the ability of a material to bounce back after it is disturbed.

Speed of sound waves: l Depends on the elasticity, density, and temperature of the medium the sound is traveling through. l Elasticity: the ability of a material to bounce back after it is disturbed. l The more dense the medium the slower sound travels through it.

Speed of sound waves: l Depends on the elasticity, density, and temperature of the medium the sound is traveling through. l Elasticity: the ability of a material to bounce back after it is disturbed. l The more dense the medium the slower sound travels through it. l The lower the temperature the slower sound travels through a medium.

Speed of sound waves: l. Air at room temp. = 343 m/s

Speed of sound waves: l. Air at room temp. = 343 m/s l. Fresh water = 1, 509 m/s

Speed of sound waves: l. Air at room temp. = 343 m/s l. Fresh water = 1, 509 m/s l. Glass = 5, 170 m/s

Properties of sound: l Loudness: Describes your perception of the energy of the sound.

Properties of sound: l Loudness: Describes your perception of the energy of the sound. l Depends on distance from the source and energy used to make the sound.

Properties of sound: l Loudness: Describes your perception of the energy of the sound. l Depends on distance from the source and energy used to make the sound. l Measured in decibels (d. B).

Properties of sound: l Loudness: Describes your perception of the energy of the sound. l Depends on distance from the source and energy used to make the sound. l Measured in decibels (d. B). l Intensity: The amount of energy a sound wave carries through an area each second.

Pitch l. A measure of how high or low a sound is.

Pitch l. A measure of how high or low a sound is. l Pitch depends on the frequency of a sound wave

Pitch l. A measure of how high or low a sound a is. l Pitch depends on the frequency of a sound wave

Pitch l. A measure of how high or low a sound a is. l Pitch depends on the frequency of a sound wave - Low pitch - High pitch - Low frequency - High frequency - Longer wavelength - Shorter wavelength

Sonar

Sonar - An instrument that uses reflected sound waves to find underwater objects

Sonar - An instrument that uses reflected sound waves to find underwater objects For example,

Sonar - An instrument that uses reflected sound waves to find underwater objects For example,

Sonar - An instrument that uses reflected sound waves to find underwater objects For example, Animals use sonar or echo location to find their prey; these sounds have such a high pitch or frequency that the human ear cannot hear

Sonar - An instrument that uses reflected sound waves to find underwater objects For example, Animals use sonar or echo location to find their prey; these sounds have such a high pitch or frequency that the human ear cannot hear

Sonar - An instrument that uses reflected sound waves to find underwater objects For example, Humans use sonar to locate or map objects Animals use sonar or echo location to find their prey; these sounds have such a high pitch or frequency that the human ear cannot hear

Doppler Effect: l Definition: The change in frequency of a wave as its source moves in relation to an observer.

Doppler Effect: l Definition: The change in frequency of a wave as its source moves in relation to an observer. Lower pitch Higher pitch

Blue Man Group Challenge! Blue Man Group l You’re HIRED! l So what am I supposed to do exactly? l

Can I use or make an instrument that already exists? l No way! You could, if you really wanted to…but wouldn’t you rather challenge yourself to invent something never seen before? C’mon, I know you can do it! Besides, building a piano is really complicated. And putting a piece of string on top of a piano isn’t really groundbreaking, either.

Let’s look at some examples! l Awesome l Not Awesome l l Shoe box with rubber bands attached Oatmeal box with beads in it or paper on top to create a drum l Tambourines made from paper plates l Bongos made from tubs and paper