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Observe video and think about how is the window being shaken?. https://www.youtube.com/watch?v=cedfX-gzHuM. Remember! . Sound is a wave! Since waves transfers energy, Sound transfers energy (but not matter) Sound = vibrations of particles.
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Observe video and think about how is the window being shaken? https://www.youtube.com/watch?v=cedfX-gzHuM
Remember! Sound is a wave! Since waves transfers energy, Sound transfers energy (but not matter) Sound = vibrations of particles
Check out this demo of how a speaker makes sound waves http://phet.colorado.edu/en/simulation/sound https://www.youtube.com/watch?v=CewacsP6TSY&feature=related
Notice the red particles. Does they ever travel across, or just vibrate longitudinally? • http://www.acs.psu.edu/drussell/Demos/waves/wavemotion.html
Are sound waves transverse or longitudinal waves? Sound waves are longitudinal waves!
Since sound waves are waves (longitudinal waves), they can be described with wave properties such as frequency and amplitude
Pitch Sound Frequency Pitch _______ is how you hear and interpret _______ Higher _________ = Higher _____ Example: Lower _________ = Lower ______ Example: Siren or whistle Frequency Pitch Rumble of Truck
20Hz-20,000Hz Humans can only hear frequencies of sound within a certain range ( )
Loudness Decibles Amplitude _________________ of a sound is measured in ___________ and is determined by the ___________________ of the wave. The higher amplitude = louder sound!
Watch this, its electrifying! • http://www.youtube.com/watch?NR=1&feature=fvwp&v=JXcZO9UFnl0
Why do you first see the lightning, and then later hear the thunder? Sound waves travel at a certain speed (no where near as fast as light waves!) The speed of the sound waves depends upon the medium (material) it is in
Does sound travel the fastest in a solid (like metal), liquid (like water) or gas (like air?) • http://www.ndt-ed.org/EducationResources/HighSchool/Sound/speedinmaterials.htm Watch the computer demo and answer the following discussion questions based on what you saw/heard What happens to the speed of sound when you change the material through which the sound travels? Through which material does sound move faster? Why do you think it is faster?
Discussion questions • What happens when you change the material through which the sound travels? • Through which material does sound move faster? Why do you think it is faster?
Speed of sound waves Sound travels fastest in solids (like metal) Second fastest in liquids (like water) Slowest in gases (like air) Why? The closer the particles are, the easier for the vibrations to transfer the energy
Interesting… • No sound in space! • Why? • Space = vacuum (no particles to vibrate and transfer energy by sound!)