Sound - The Nature of Sound Sound Waves Sound is a disturbance that travels through a medium as a longitudinal wave. As a gong vibrates, it creates sound waves that travel through the air.

Sound - How You Hear Sound The Human Ear The outer ear funnels sound waves, the middle ear transmits the waves inward, and the inner ear transforms sound waves into a form that travels to your brain.

Sound - Music Sound Quality The sound quality of musical instruments results from blending a fundamental tone with its overtones. Resonance also plays a role in sound quality.

Sound - The Nature of Sound Interactions of Sound Waves Sound waves reflect off objects, diffract through narrow openings and around barriers, and interfere with each other.

Sound - The Nature of Sound The Speed of Sound The speed of sound depends on the elasticity, density, and temperature of the medium the sound travels trough.

Sound - Properties of Sound Loudness The loudness of different sounds is compared using a unit called the decibel (dB).

Sound - Properties of Sound The Doppler Effect The change in frequency of a wave as its source moves in relation to an observer is called the Doppler effect. When a sound source moves, the frequency of the waves changes because the motion of the source adds to the motion of the waves.

Sound - Properties of Sound The Doppler Effect When the plane travels almost as fast as the speed of sound, the sound waves pile up in front of the plane. This pile up is the “sound barrier.”

Sound 12-8 Shock Waves and the Sonic Boom Shock waves are analogous to the bow waves produced by a boat going faster than the wave speed in water.

Sound - Properties of Sound When you sing, you change pitch using your vocal cords. Your vocal cords are located in your voice box, or larynx. Changing Pitch

Sound - Using Sound Echolocation Some animals, including bats and dolphins, use echolocation to navigate and to find food.

Sound - Using Sound Sonar A sonar device sends out ultrasound waves and then detects the reflected waves.

Sound Temperature and the Speed of Sound The speed of sound in dry air changes as the temperature changes. The graph shows data for the speed of sound in air at temperatures from –10ºC to 20ºC. - The Nature of Sound

Sound Temperature and the Speed of Sound The speed at –10ºC is 325 m/s. Reading Graphs: What is the speed of sound in air at –10ºC? - The Nature of Sound

Sound Temperature and the Speed of Sound The speed of sound increases as air temperature increases. Interpreting Data: Does the speed of sound increase or decrease as temperature increases? - The Nature of Sound

Sound Temperature and the Speed of Sound At 30ºC, the speed of sound might be 349 m/s. Predicting: What might be the speed of sound at 30ºC? - The Nature of Sound

Sound - Music Groups of Musical Instruments There are three basic groups of musical instruments: stringed instruments, wind instruments, and percussion instruments.

Sound - The Nature of Sound Elasticity Elasticity is the ability of a material to bounce back after being disturbed. You can model elasticity by representing the particles in a medium as being held together by springs.

Sound - The Nature of Sound Density Density is how much mass there is in a give volume. The volumes of the cubes are the same, but the brass has more mass.

Sound Main Idea Detail Identifying Main Ideas As you read the section “Interactions of Sound Waves,” write the main idea–the biggest or most important idea–in a graphic organizer like the one below. Then write three supporting details that further explain the main idea. Sound waves interact with objects and with other sound waves. Reflection occurs when sound waves strike a surface. Sound waves can diffract around corners and through openings. The interference of sound waves can be constructive or destructive. - The Nature of Sound

Sound Links on Sound Click the SciLinks button for links on sound. - The Nature of Sound

Sound Speed of Sound Click the Video button to watch a movie about the speed of sound. - The Nature of Sound

Sound End of Section: The Nature of Sound

Sound - Properties of Sound Pitch The pitch of a sound that you hear depends on the frequency of the sound wave.

Sound Outlining An outline shows the relationship between main ideas and supporting ideas. As you read, make an outline about the properties of sound. Use the red headings for the main ideas and the blue headings for the supporting ideas. Properties of Sound I.Loudness A.Energy of a Sound Source B.Distance From a Sound Source C.Measuring Loudness II.Pitch A.Pitch and Frequency B.Changing Pitch III.Doppler Effect A.What Causes the Doppler Effect? B.What Causes Shock Waves? - Properties of Sound

Sound More on the Properties of Sound Click the PHSchool.com button for an activity about the properties of sound. - Properties of Sound

Sound Pitch Click the Video button to watch a movie about pitch. - Properties of Sound

Sound End of Section: Properties of Sound

Sound Musical Instruments Activity Click the Active Art button to open a browser window and access Active Art about musical instruments. - Music

Sound Previewing Visuals When you preview, you look ahead at the material to be read. Preview Figure 15. Then write two questions that you have about the diagram in a graphic organizer like the one below. As you read, answer your questions. Musical Instruments Q. How is pitch changed in each type of instrument? A. By changing the frequency of the vibrations Q. How is the loudness changed in each type of instrument? A. By changing the energy of the vibrations - Music

Sound End of Section: Music

Sound Sequencing Sequence is the order in which the steps in a process occur. As you read, make a flowchart that shows how you hear sound. Put the steps of the process in separate boxes in the order in which they occur. How You Hear Sound The outer ear funnels sound waves into the ear canal. Sound waves make the eardrum vibrate. Tiny bones in the middle ear transmit vibrations to the inner ear. Vibrations in the cochlea of the inner ear send messages to the brain. - How You Hear Sound

Sound End of Section: How You Hear Sound

Sound FeatureEcholocationSonar Comparing and Contrasting As you read, compare and contrast echolocation and sonar by completing a table like the one below. Type of wave Ultrasound Medium(s) Air, water Water Purposes Navigate, find food Find water depth, sunken objects, schools of fish - Using Sound Using Sound

Sound More on Sonar Click the PHSchool.com button for an activity about sonar. - Using Sound

Sound End of Section: Using Sound

Sound Graphic Organizer Longitudinal waves Sound has properties Intensity DensityPitch travels as speed depends onis heard as Frequency ElasticityTemperatureLoudness

Sound End of Section: Graphic Organizer