Sound Waves Physics Ms Jeffrey Sound Waves Sound

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Sound Waves Physics- Ms. Jeffrey

Sound Waves Physics- Ms. Jeffrey

Sound Waves • Sound is a wave that is created by vibrating objects and

Sound Waves • Sound is a wave that is created by vibrating objects and propagated through a medium from one location to another. • There is an original source of the wave, some vibrating object that disturbs the first particle of the medium. • A sound wave is transported from one location to another by means of particle-to-particle interaction. • Particles push against each other and displace those around it.

Sound Waves • Sound waves in a medium are longitudinal waves • particles of

Sound Waves • Sound waves in a medium are longitudinal waves • particles of the medium vibrate parallel to the direction that the sound wave moves. • There are regions in the air where the air particles are compressed together and other regions where the air particles are spread apart. • Called compressions and rarefractions • The wavelength is the distance from one compression to the next compression

Frequency • The frequency of a wave refers to how often the particles of

Frequency • The frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium. • As a sound wave moves through a medium, each particle of the medium vibrates at the same frequency. • The human ear is capable of detecting sound waves with a wide range of frequencies, ranging between approximately 20 Hz to 20, 000 Hz.

Pitch • The sensation of a frequency is commonly referred to as the pitch

Pitch • The sensation of a frequency is commonly referred to as the pitch of a sound. • A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low frequency sound wave. • the note "C" on a piano has a frequency of 262 Hz and the note "E" has a frequency of 327 Hz. That C-note is a lower pitch than the next E simply because of their differing frequencies.

Intensity • The amount of energy that is transported past a given area of

Intensity • The amount of energy that is transported past a given area of the medium per unit of time is known as the intensity • The greater the amplitude of vibrations of the particles of the medium, the louder the sound will be. • The faintest sound that a human ear can detect is known as the threshold of hearing (TOH). • 0 d. B • The scale for measuring intensity is the decibel scale.

Speed of Sound • Like any wave, the speed of a sound wave refers

Speed of Sound • Like any wave, the speed of a sound wave refers to how fast the disturbance is passed from particle to particle. • Speed = distance/time • v=fλ or v=λ/T • Calculate the speed of sound for a sound that has a frequency of 20, 000 Hz, and a wavelength of 20 m. • We see a bolt of lightning and 4 s later we hear thunder. If the speed of sound in air is 321 m/s, how far away is the lightning?

Wave Interference • Wave interference is the phenomenon that occurs when two waves meet

Wave Interference • Wave interference is the phenomenon that occurs when two waves meet while traveling along the same medium. • Constructive interference occurs along the medium where the two interfering waves have a displacement in the same direction.

Wave Interference • Destructive interference occurs along the medium where the two interfering waves

Wave Interference • Destructive interference occurs along the medium where the two interfering waves have a displacement in the opposite direction. • The interfering pulses have the same maximum displacement but in opposite directions. • The result is that the two pulses completely destroy each other when they are overlapped.

Superposition • When two waves interfere, the resulting displacement of the medium at any

Superposition • When two waves interfere, the resulting displacement of the medium at any location is the sum of the displacements of the individual waves at that same location. • Example: Red = 1 m, Blue = -2 m, Resultant Displacement=