The Nature of Sound

The Nature of Sound

SOUND WAVESSound waves carry energy through a medium as a LONGITUDINAL WAVE.The ENERGY disturbs the medium by causing the particles next to each other to COMPRESS.Sound travels through solids, liquids, and gases.

MAKING WAVESAll objects can be made to vibrate, by plucking, striking or blowing across.They will vibrate at their NATURAL or FUNDAMENTAL FREQUENCY.

This FREQUENCY is determined by the SIZE, SHAPE, DENSITY & MATTER the object is made of.STOMP!SOUND WAVES INTERACT WITH MATTERSound waves may reflect when they hit a surface.Sound waves can DIFFRACT through an opening, or bend around a corner.

Perception of SoundLOUDNESS Depends on HOW MUCH ENERGY is put behind it (amplitude).We measure LOUDNESS in DECIBELS (dB)

MORE AMPLITUDE = MORE DECIBELS = INTENSITY!

PITCHDescribes of how HIGH or LOW the sound seems.Pitch is caused by the number of VIBRATIONS or the FREQUENCY of the sound wave.

FREQUENCY = # of wavesA LOT OF VIBRATIONS = HIGH FREQUENCY = HIGH PITCH

SLOW OR FEWER VIBRATIONS = LOWER FREQUENCY = LOW PITCHGLASSES

SIZE AFFECTS FREQUENCY!

The SMALLER an object, the MORE the WAVE REFLECTS inside it, soThe GREATER the # of Vibrations!_________ Frequency = _______ Pitch

The BIGGER an object, the SLOWER the VIBRATIONS, The LOWER the # of VIBRATIONS._________ Frequency = _______ Pitch

Infrasound Ultrasound

HUMANS have a limited RANGE of PERCEPTION of SOUND WAVES

Sound waves below the normal human range of hearing. Sound waves above the normal human range of hearing.MOSQUITO RINGTONE HEARING TEST

Speed of SoundDepends on the density and temperature of the medium the wave travels through.LOWER TEMP OR GREATER DENSITY = FASTEST SPEED (SOLID)

HIGHER TEMP ORLOWER DENSITY = SLOWER SPEED (GAS)HANGER DEMO ANIMATION DensityHow much matter, or mass, there is in a given amount of space, or volume. Sound travels fastest in denser mediums.

TemperatureSound travels more slowly at higher temperatures than at lower temperatures.

The Doppler EffectThe change in frequency of a sound wave caused by movement of the sound source or the observer.

What do you noticeabout the waves?Wavelength?Frequency?

What would cause the amplitude to change?

What happens tothe waves in front of him?Wavelength?Frequency?

How would thischange whatwe hear?

Behind him?Shock WavesForm when sound waves overlap and break through the wave barrier, releasing a huge amount of energy (sonic boom!)

VIDEOTHE SOUND SONG

When someones making a sound.Well, the atoms start moving around.They vibrate into your ear.Movin your eardrum, and makin you hear.

CHORUS: (I think its time we) Stop, listen to that sound. Resonating through us all around!

Compressions happening hereLongi-tud-inal waves will appearRar-e-factions appear over thereThrough solids, and liquids. Even through air!

The eardrum vibrates and repeatsHammer and anvil will pound out the beatsThe cochlea moves fluid aroundThe cilia will wave and the brain makes a sound!CHORUS: (I think its time we) Stop, listen to that sound. Resonating through us all around!

Be careful of the decibels you hearMore than 100 might be damaging your earThe loudness can cause them to ringYoull get tinnitus, or have trouble. Cant hear anything!

POP GOES tHE WEASELG CC DD EGECG CC D F E C G CC DD EGECA D F E C

TWINKLE TWINKLE LITTLE STARCC GG AA GFF EE DD CGG FF EE DGG FF EE DCC GG AA GFF EE DD CWarm-upWhy is the speed of sound faster in colder temperatures?

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