Sound
-
Sound is a form of energy that travels through matter as
waves
Sound waves travel more slowly than light waves
Speed 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 wave
Trough – 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 rarefactions
or the amount of energy in a wave
Compression
is the part of the wave where particles are pushed together
Greater air pressure
Rarefaction
is the part of the wave where there are fewer particles than normal.
Lower air pressure
Quality of Sound
Pitch
Measures highness or lowness of sound
Relates to the frequency of the waves
High frequency is a high pitched sound
Pitch
Low
frequency
is a low
pitched
sound
Pitch & Amplitude
High frequency = high sound (pitch)
Low frequency = low sound (pitch)
Small amplitude = quiet sound
Large 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!
SONAR
SOund 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.
My what big ears you have!
Semicircular canal
Anvil
Cochlea &
Auditory Nerve
Hammer
Ear Canal
Eustachian tube
Ear Drum
Stirrup
The Ear
Eardrum 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 !!