Physics of Sound | Properties, types, Applications and fact's

Everyone familiar with word 'Sound'. After listening the word the things which come's in our mind is music, party, noise etc. But, the question is are really familiar with the meaning of Sound.

So today, I am going to Cover all the topics related to term Sound with their properties and with their examples from real world.

Highlights of Article:

○ Sound and its properties.

○ Frequency or pitch

○ Loudness
○ Speed of sound

○ ECHO

○ SONAR

○ Resonance

○ Doppler effect

Sound:

Sound is a form of energy which required a medium ( solid, liquid or gas ) for a travelling one place to another.
Sound waves cannot travel through vacuum.
Sound is a longitudinal wave which form congiqutive compression and rare fraction.
The speed of sound in a dry air at 0°C is 331m/s (or 750 miles/hour).
The speed of sound is fastest in solid like steel, slower in liquid and poor in air.
Speed of sound is directly proportional to elasticity of medium.
The presence of water vapour in the air increase the speed of sound
The speed of sound in air increases at the rate of 0.61m/s for each degree Celsius rise in temperature above 0°Celsius.
Human ear is a sensitive to the sound wave of frequency between 20Hz to 20,000Hz (Audible range).
Sound wave having frequency less than 20Hz are called Infrasonic wave and greater than 20,000Hz are called Ultrasonic wave.
The Animals and whale's can hear Infrasonic wave. The geological phenomena like Earth-quick or volcanic eruptions produces Infrasonic wave.
The animal like cat, bat and mosquito can produce and as well as hear Ultrasonic wave.

Frequency (Pitch)

The pitch or shrilness of sound depends upon frequency of sound. A sound wave having higher frequency having higher pitch, and as pitch increases the shrilness of sound increases.
The pitch of women is higher than man voice.

Loudness

Loudness of sound wave depends upon amplitude and its related to energy of the wave.
Loudness is a measure is Decible(db).
The sound wave having a loudness of 85db or more is considered as a noise pollution and can damage Ear-Drum or can cause hearing impairment.
All strings instrument (guitar) have sound box attached to it to increase the loudness of sound.
Example Playing guitar.
A string of guitar is plugged a small amount of air vibrate which is not aduable, but the sound box attached to the string instrument causing forced vibration, and sets a large amount of air column (air mass) into the vibration. Thus the sound become a audible and the loudness of sound increases.
A loud speaker has a large vibrating cone with the large surface area to increase the loudness of sound
The Speed of sound is a slower than the speed of light due to the these thunder is a hurt much after the flash of lightning seen.
The sound of jet plane or Supersonic plane is a heard much after then seen.

Speed of sound

The speed of sound varies with material to material. List of materials having various speed.

Factors affecting the speed of Sound

There some physical factors that can affect the sound propagation.

Wind Gradient:

Sound propagating against the wind would bend upwards. while, Sound propagating along the wind would bend downwards.

Atmospheric Turbulence:

While sound wave traveling in atmosphere(turbulent), it may be scatter due to velocity fluctuation of the medium.

Temperature Gradient:

Sound waves travel faster near the surface of the earth due to warm atmosphere.

Question: which property of sound changes with respect to temperature?The wavelength of the sound changes with respect to change in temperature.

Reflection of Sound (ECHO):

Reflection of sound wave from any object placed at minimum distance 17m and heard after 0.1sec (1/10 of sec) after the original sound is called ECHO.

if the distance between the source and the object is less than 17 the deflection produce is called reverberation. It cannot be clearly here and it produce when the time is taken is less than 0.1 seconds.

SONAR (Sound navigation and ranging)

it is a technique which use's ECHO of ultrasonic wave. because it have a high frequency.

Use's:- for a measuring depth of sea bed or locating Submerged object in a sea water.

Ultrasonic waves are also used for making underground structure for oil, Minerals and natural gas as well as dectating flows in the interior of solid and destroying micro-organism.

Ultrasonic waves are also used in the ultrasonography also known as ultrasound.

Ultrasound is a basically used for abdomen diagnosis.

Resonance

Two object moving with the same natural frequency are said to be resonance.
Resonance result in Increase in amplitude or Increases in loudness.
Example

By crossing a Suspension Bridge Soldier are order to break step to avoid the phenomenon of resonance. If it do not take place it may cause damage to the bridge.
In a vehicle vibration of a rear view mirror at a particular Engine speed is due to the phenomenon of resonance.

Doppler Effect

it is a change in the frequency of the sound wave due to the motion of the source of the observer.

Frequency of a sound appears to the higher, When the source and observer come closer to each other (or distance between the source and observer decreases). Frequency decreases, When the source or observer move away from each other (Distance increasing).

Due to the Doppler effect visual of train appear to be sriller when its approaches the listeners then when the train move away from the listener.

Doppler Effect used as astronomy. by the help of Doppler Effect the rotation of star can be determined.

Sonic Bomb

A Supersonic plane (faster than sound) produces a cone of sound call Shock wave. this shock-wave reaches to listener and create a Short of loud Explosion is known as Sonic bomb.

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