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Sound Waves

Sound Waves. Sound. A form of energy that causes molecules of a medium to vibrate back and forth in a series of compressions and rarefactions as a longitudinal wave. http://static.howstuffworks.com/gif/noise-canceling-headphone-8.jpg. Characteristics of Waves.

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Sound Waves

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  1. Sound Waves

  2. Sound • A form of energy that causes molecules of a medium to vibrate back and forth in a series of compressions and rarefactions as a longitudinal wave http://static.howstuffworks.com/gif/noise-canceling-headphone-8.jpg

  3. Characteristics of Waves • Amplitude; The maximum distance that molecules are displaced from their resting position. • Indicates the energy of wave. http://www.bargerbarger.com/personal/wp-content/uploads/2008/05/wave.png

  4. Characteristics of Waves • Wavelength; The distance between 2 consecutive crests or troughs of a wave measure in centimeters and meters. http://www.astro.cornell.edu/academics/courses/astro2201/images/wavelength.gif

  5. Characteristics of Waves • Frequency; The number of complete waves or complete cycles per unit of time. • Measured in Hertz Hz http://www.open2.net/open2static/source/file/root/1/0/26/263839/wave_length_choc_diag3.jpg

  6. Characteristics of Waves • Sound waves also have the characteristic of interaction.

  7. Determining sound • Intensity • Frequency • Quality

  8. Following Effects on the Human Ear • Loudness • Pitch • Timbre

  9. Intensity and Loudness • The amount of energy in a wave determined by the amplitude of sound wave. • Large Amplitude = Large Intensity = Increased Loudness • Measured in Decibels

  10. Frequency and Pitch • Pitch • How high or low the sound is (NOT how loud or soft). • Determined by frequency • High frequency = High pitch • Measured in Hertz (Hz) • Human ears can hear in a range from 20 to 20,000 Hz.

  11. Ultrasonic • A pitch or frequency higher than 20,000 hertz. http://vb-lessenergy.com/sonic_sound_files/page12_1.jpg

  12. Sonar • Uses ultrasonic waves to detect solids. http://mainland.cctt.org/istf2006/images/496px-Sonar_Principle_EN.svg%5B1%5D.png

  13. Transmitting Sound • Requires a Medium

  14. 2 Things that Affect the Transmission of Sound • 1. Elasticity of Materials • Materials that are more elastic transmit sound easier. • Metals/Solids are more elastic than liquids and gases.

  15. 2 Things that Affect the Transmission of Sound • 2. Arrangement of molecules of the medium. • Molecules that are close together transmit sound easier. • Solids transmit best because the molecules are close together. • A long time ago people would put their ear on the railroad tracks to see how close the train was.

  16. Speed of Sound • In the air it is approximately 340 m/s. • Affected by 2 factors: • Temperature • As temperature increases speed of sound increases. • Nature of the medium • Sound travels faster in the most elastic materials • Density increases speed of sound decreases.

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