2. WHAT IS SOUND ?
Vibrations that travel through the air or another
medium and can be heard when they reach a
persons or a animals ear.
Its a form of energy in the form of waves.
3. TYPES OF SOUND WAVES
Sound Waves
Longitudinal
Waves
Transverse
Waves
The particles of the medium oscillate about the
central or mean positions, in a direction parallel to
propagation of the wave. Such waves are called
Longitudinal Waves.
The particles of the medium oscillate
perpendicular to the direction of propagation of
the wave such waves are called Transverse Waves.
4.
5. Amplitude is the maximum value of pressure or density, it
is denoted by “A”.
Value of the amplitude determines its strength or
loudness.
Frequency : it is the number of occurrences of a repeating
event per unit of time.
Frequency Wave : it is measured as number of wave cycles
that occur in one second.
1Hertz = 1 wave cycle per second
It is the speed of the vibration and determines the pitch of
the sound
6. VELOCITY OF SOUND
The distance covered by a point on the wave (for Eg. The point
of highest density or lowest density) in unit time is the velocity
of the sound wave.
Velocity =
𝑫𝒊𝒔𝒕𝒂𝒏𝒄𝒆
𝑻𝒊𝒎𝒆
At any point on the sound wave covers a distance equals to
wavelength in time T.
Velocity =
𝑾𝒂𝒗𝒆𝒍𝒆𝒏𝒈𝒕𝒉
𝑻𝒊𝒎𝒆 𝑷𝒆𝒓𝒊𝒐𝒅
Velocity of sound = Wavelength * Frequency
7. State Substance Speed
Solid Aluminum 5420
Nickel 6040
Steel 5960
Iron 5950
Brass 4700
Glass 3980
Liquid Sea Water 1531
Pure Water 1498
Ethanol 1207
Methanol 1103
Gas Hydrogen 1284
Helium 965
Air 346
Oxygen 316
Sulphur dioxide 213