sound - the nature of sound sound waves sound is a disturbance that travels through a medium as a...
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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 QualityThe 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.”
Sound12-8 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 is325 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 Detail Detail
Identifying Main IdeasAs 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 aboutthe 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
OutliningAn 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. LoudnessA. Energy of a Sound
SourceB. Distance From a
Sound SourceC. Measuring Loudness
II. PitchA. Pitch and FrequencyB. Changing Pitch
III. Doppler EffectA. 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 activityabout 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 VisualsWhen 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
SequencingSequence 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
Feature Echolocation Sonar
Comparing and ContrastingAs you read, compare and contrast echolocation and sonar by completing a table like the one below.
Type of wave Ultrasound Ultrasound
Medium(s) Air, water Water
Purposes Navigate, find foodFind 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
Density Pitch
travels as
speed depends on is heard as is heard as
Frequency
Elasticity Temperature Loudness
Sound
End of Section:Graphic Organizer