SOUND Vibrations that travel through air or another medium and can be heard when they reach a persons or animals ear is defined as sound USES OF MULTIPLE REFLECTION OF SOUND Megaphones and musical instruments Megaphones or loudhailers horns musical instruments are all designed to ID: 489070
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Slide1
SOU
NDSlide2
SOUND
Vibrations that travel through air or another medium and can be heard when they reach a person’s or animal’s ear is defined as sound .Slide3
USES OF MULTIPLE REFLECTION
OF SOUND….Slide4
Megaphones and musical instruments Megaphones or loudhailers, horns, musical instruments are all designed to send sound in a particular direction without spreading it in all directions. In these instruments, a tube followed by a conical opening reflects sounds successively to guide most of the sound waves from the source in the forward direction.
1.Slide5
shehanaiSlide6
2.
In stethoscope the sound of a patient's heartbeat is guided by along the tube of the stethoscope to the doctor's ears by multiple reflections of sound.Slide7Slide8
Curved ceilings of concert halls, conference halls and cinema halls are made curved so that sound after reflection reaches all the corners of the halls.
3.Slide9Slide10
RANGE OF
HEARINGSlide11
RANGE OF HEARING IN
LIVING THINGSSlide12
HEARING RANGE
Hearing Range
usually describes the range of frequencies that can be heard by an animal or human, though it can also refer to the range of levels. In humans the audible range of frequencies is usually said to be 20 Hz (cycles per second) to 20 kHz (20,000 Hz), although there is considerable variation between individuals, especially at the high frequency end, where a gradual decline with age is considered normal.Slide13Slide14Slide15
HEARING RANGE IN HUMANS
In a human, sound waves funnel into the ear via the external ear canal and hit the eardrum (tympanic membrane). Consequently the compression and rarefaction of the wave set this thin membrane in motion, causing the middle ear bones (the ossicles; malleus, incus and stapes) to move. The number of sound pressure level vibrations (sonic waves) per second denotes the frequency.
Infrasonic (below hearing), sonic (aural), and ultrasonic (above hearing) frequencies are measured in Hertz (Hz); one Hertz is one cycle wave (or singular pressure wave in audionics) per second.Slide16
Humans
have developed culture and technology
such
as
music,
telephone
and
radio .
that allows
them to generate,
record
,
transmit, and broadcast sound. The scientific study of
human sound perception is
known as
Psychoacoustics.
P
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a
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s
t
i
c
s.Slide17
INFRASOUND
If we could hear infra sound we could hear vibrations of pendulum just like how we year flattering of the wings of the bee.
Infra sound producing animalsSlide18
Ultrasound Slide19
Earthquakes produce low frequency infrasound before the main shock waves begin which alerts the animalsSlide20
HEARING RANGE IN DOGS
The hearing ability of a dog is dependent on its breed and age. However, the range of hearing is approximately 40 Hz to 60 kHz, which is much greater than that of humans. As with humans, some dog breeds become more deaf with age, such as the German Shepherd and Miniature Poodle. When dogs hear a sound, they will move their ears towards it in order to maximise reception. In order to achieve this, the ears of a dog are controlled by at least 18 muscles. This allows the ears to tilt and rotate. Ear shape also allows for the sound to be more accurately heard.Slide21
DOG’S
EARSlide22
HEARING RANGE IN BATS
Bats require very sensitive hearing to compensate for their lack of visual stimuli, particularly in a hunting situation, and for navigation. Their hearing range is between 20 Hz and 150 kHz. They locate their prey by means of echolocation. A bat will produce a very loud, short sound and assess the echo when it bounces back. The type of insect and how big it is can be determined by the quality of the echo and time it takes for the echo to rebound; there are two types; constant frequency (CF), and frequency modulated (FM) calls that descend in pitch.Slide23
HEARING RANGE IN BATSSlide24
HEARING AIDSlide25
A
hearing aid
is an electroacoustic device which typically fits in or behind the wearer's ear, and
is designed to amplify and modulate sound for the wearer. Earlier devices,
known as ear trumpets or ear horns, were passive funnel-like amplification cones designed to gather sound energy and direct it into the ear canal. Similar devices include the bone anchored hearing aid, and cochlear implant.
WHAT IS A HEARING AID??Slide26
H
E
A
R
I
N
G AIDSlide27
THANK
YOU !!Slide28
QUESTION
Why are the ceilings of concert halls curved?
Ceilings of concert halls are curved so that sound after reflection (from the walls) spreads uniformly in all
directions.
20 Hz to 20,000 Hz
What is the audible range of the average human ear?Slide29
What is the range of frequencies associated with
(a) Infrasound?
(b) Ultrasound?
(a) Infrasound has frequencies less than 20 Hz.(b) Ultrasound has frequencies more than 20,000 Hz.
What is a hearing aid? What is it used for?
Hearing aid is an electronic battery operated device for people with hearing loss.Slide30
Give any one use of multiple reflection of sound.
What is the hearing range of an elephant?
Below 20 HzSlide31
GROUP-4
NEETHY
NEHA
POOJA
PRAVITHA
QAYNAT