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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 !!