This report summarizes key aspects of sound, including: 1) Pitch is determined by frequency, with higher frequencies producing higher pitches. Speed of sound depends on temperature and medium, averaging 343 m/s in air at 20°C. 2) The Doppler effect causes changes in perceived frequency due to relative motion between source and observer. An ambulance siren's pitch rises as it approaches and falls as it passes by. 3) Sound intensity decreases with distance from the source and depends on factors like amplitude, source area, density of transmitting medium, and presence of surrounding objects. Intensity is measured in watts per square meter.

1. 9/7/2013
Newports Institute of Communication & Economics
SOUND REPORT
Submitted To:
Miss Faryal
Submitted By:
Muhammad Saqib Ishaq
Zuhaib Ali
Abdul Ahad Sheikh

2. Final Report on Sound
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Table of Contents
Introduction of Sound ...........................................................................................3
Pitch of Sound....................................................................................................3
Speed of Sound ..................................................................................................4
Frequency of Sound...........................................................................................5
The Doppler Effect................................................................................................5
Examples of Doppler Effects.............................................................................5
Intensity of Sound.................................................................................................6
Unit of Sound Intensity......................................................................................6

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Introduction of Sound
Sound is one kind of longitudinal wave, in which the particles oscillate to and
fro in the same direction of wave propagation. Sound waves cannot be
transmitted through vacuum. The transmission of sound requires at least a
medium, which can be solid, liquid, or gas.
Pitch of Sound
Pitch is the frequency of a sound as perceived by human ear. A high frequency
gives rise to a high pitch note and a low frequency produces a low pitch note.

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Speed of Sound
The speed of sound is the distance travelled during a unit of time by a sound
wave propagating through any medium.
The speed of sound in air actually depends on the temperature of the air.
In dry air at 20 °C, the speed of sound is 343.2 m/s. This is 1,236 km/h, or about
a kilometre in three seconds.
The formula to calculate the speed of sound at a different temperature is as
below.
V = 331.5m/s + 0.6T
Where:
V = velocity of sound in m/s
T = temperature in °C
Speed of Sound in different Material
Material Speed of Sound
Rubber 60 m/s
Air at 40o
C 355 m/s
Air at 20o
C 343 m/s
Lead 1210 m/s
Gold 3240 m/s
Glass 4540 m/s
Copper 4600 m/s
Aluminum 6320 m/s

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Frequency of Sound
Frequency of Sound is characterized as a periodic vibration whose frequency is
audible to the average human.
The formula to calculate the Frequency of Sound is as below.
v = f λ
Where:
v = speed in meters/second (m/s)
f = frequency in Hertz (Hz)
λ = wavelength in meters (m)
If the sound you are measuring is at a constant temperature then the velocity
will be constant about 340 m/s.
The Doppler Effect
Doppler Effect is the apparent change in the frequency of a sound caused by the
motion of either the listener or the source of the sound.
Examples of Doppler Effects
Imagine that you are standing on a corner as an ambulance rushes by. As the
ambulance passes, the sound of the siren changes from a high pitch to a lower
pitch. Why? Do the sound waves produced by the siren change as the
ambulance goes by? How does the motion of the ambulance affect the sound?

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Intensity of Sound
Sound intensity is defined as the sound power per unit area A.
The formula to calculate the Sound Intensity is as below.
I = PA
Where:
I = Intensity
P = Pressure of sound,
A = Area
The intensity of sound decreases with the distance from the source of sound.
The intensity of sound depends on:
 Amplitude of vibrations of the source.
 Surface area of the vibrating source.
 Distance of the source from the observer.
 Density of the medium in which sound travels form the source.
 Presence of other surrounding bodies and
 The Motion of the medium.
Unit of Sound Intensity
The units for sound intensity in S.I system is (watts per square metre) W/m2
. It
is a physical quantity.