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Sound
Sound is a form of energy that travels through matter as waves
Sound waves travel more slowly than light wavesSpeed of light waves is 300 million m/s
Sound is 346 m/s
• Sound does not travel in a vacuum like light!
• Sound travels fastest through a solid because
the particles of a solid are close together
• Sound travels slower through a liquid because the particles are spread out.
• Sound travels the slowest through air because
the particles in a gas are so far apart or spread out (just the opposite of light).
Sound travels in waves like light!Crest – highest point of the waveTrough – lowest part of the wave
Sound waves are measured according to:
Frequency the number of waves or vibrations in a specific unit of time
(like a second)
Wavelength measurement from the crest of one wave to another crest
Vibration Back and forth movements of matter
Waves are also measured by Amplitude
the difference between compressions and rarefactionsor the amount of energy in a wave
Compression is the part of the wave where particles are pushed together
Greater air pressureRarefaction
is the part of the wave where there are fewer particles than normal.Lower air pressure
Quality of Sound
PitchMeasures highness or lowness of soundRelates to the frequency of the waves
High frequency is a high pitched sound
PitchLow
frequency is a low pitched sound
Pitch & AmplitudeHigh frequency = high sound (pitch)Low frequency = low sound (pitch)
Small amplitude = quiet soundLarge amplitude = loud sound
Frequencies are measured in a unit called a hertz (Hz)Different animals can hear different ranges of hertz
Elephants can hear very low frequencies. They even communicate across many miles in a frequency so
low, humans can not hear them!
Bats and dolphins can hear very high frequencies!
SONARSOund Navigation And Ranging
When animals use sonar, it is called Echolocation or biosonar .Just like the sonar that is used by humans, the animals use a
series of echoes to locate each other and find prey.
Loudness!Decibel – Unit used to measure the volume or intensity of sound
Volume describes how loud or soft
Intensity is a measure of the energy of a sound wave
Breathing 10 dB
Perfect decibel for a classroom?????0!!!!!!!!!!! & to get fun Friday!
Resonance or Timbre Quality of a musical tone
Who do you think has the best resonance?
Temperature makes a difference to sound!
Hey, can’t you hear me?
No man, it’s too cold
where you are!
Sound moves faster at higher temperatures!Particles of matter move faster at higher temperatures
because they take less time to collide and pass along the waves of energy.
Ear Canal
Hammer
Anvil
Ear Drum Stirrup
Eustachian tube
Cochlea &Auditory Nerve
Semicircular canalMy what big ears you have!
The EarEardrum is connected to the hammer, anvil, and stirrup
3 tiny bones that transmit vibrations
Auditory nerve – transmits information to brain
Eustachian tube – connects middle ear to the throat keeps even air pressure in your ear
Semi-circular canals – help you keep your balance
Man, that’s some
vibration !!