“The best therapy is beach therapy”.
Did you hear that?
Hearing is the sense by which we detect and recognise
sounds around us.
Sound is a form of energy produced by vibrations.
Sound waves are Longitudinal waves
Can you hear sound in space?
Sound waves rely on the mechanical movement of particles to
propagate. Hence, sound cannot travel through vacuum.
https://amrita.olabs.edu.in/?sub=1&brch=1&sim=83&cnt=4
Terms of sound waves
The
maximum
displacement
of
the particles on
either side of the
medium.
Amplitude
Wavelength, 𝝺
Wavelength
Distance between
two
consecutive
compressions or
rarefactions.
Terms of sound waves
Frequency
Number of
vibrations produced
in one second.
Time period
Time taken by one
complete wave.
Wave Equation 𝒗 = 𝒇𝞴
Speed of sound in different media
Speed : Solid > Liquid > Gas
Why are sounds different?
Loudness: Amplitude
Pitch: Frequency
Quality: Waveform
Does sound reflect?
Sound reflection occurs when sound waves bounce back
from the surface of a solid or liquid.
The phenomenon of multiple reflection of sound is used to
amplify and to concentrate sound in a particular direction.
Why do we hear echoes?
Echo is the repetition of sound even after the source has
stopped vibrating.
Conditions:
1. The minimum distance between the
source and the reflecting surface
should be 17.2 m.
2. The size of the reflector must be
larger than the wavelength of the
sound.
3. Sound must be loud enough.
What is reverberation?
The repeated reflection that results in the persistence of
sound is called reverberation.
Reverberation
Echo
Ultrasonic sound
The sounds of frequencies higher than
20,000 Hz are called ultrasonic sounds
or ultrasounds.
Echolocation
Metal Block
Ultrasound Scan
An ultrasound scan is used to examine internal organs.
Echocardiogram
Fetal Ultrasound
Ultrasound Cleaning
Device uses ultrasound to remove contaminants from objects.
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