Sound

Sound plays an important role in our life; Sound helps us to communicate with one another.Sound is so important because animals are able to hear events all around them, no matter where their attention is focused or not.

Sound is produced by the vibrations of a body and is transmitted through material media in pressure waves made up of alternate condensations (forcing of the molecules of the medium together) and rarefactions (pulling of the molecules of the medium away from one another).

Sound travels through a medium solid, liquid and gas. It cannot travel through vacuum.

The loudness of sound depends upon its amplitude. , larger the amplitude of vibration the louder is the sound and vice versa.

Take metal dish pour water into it, strike its edge with a spoon, you will hear a sound, now again strike the edge of dish and look at the surface of water inside it, you will observe that vibrating dish producing sound along with wave in water. This shows that there is vibration in dish which is producing sound.

Vibrating part of Veena that produces sound is stretched string and Vibrating part of Tabla that produces sound is stretched membrane.

Vibrating part of Flute that produces sound is air column.

Manjira, ghatam, not and kartal are some of the instruments that which are simply beaten or struck to produce melodious music.

The string of the sitar is plucked it vibrate to produce sound, along with string other parts infact the whole instrument is forced to vibrate, and it is the sound of the vibration of the instrument that we hear.

Yes, while speaking or singing our voice box or larynx which is located at the upper end of the wind pipe vibrates.

There are two vocal cords which are stretched across the voice box or larynx in such a way that it leaves a narrow slit between them for the passage of air, when the lungs force air through the slit, the vocal cords vibrate producing sound.

Fill a bucket with water and shake a bell under the water with one hand make sure that the bell should not touch the body of the bucket. Now place your ear gently on the water surface, you will hear the sound of the ringing bell, thus we can say that sound can travel through water.

Take a metal rod and hold its one end to your ear, ask your friend to tap at the other end of metal rod you will hear the sound of tapping, thus this proves that sound can travels through solid.

Sound can travels through liquid.Fill a bucket with water and shake a bell under the water with one hand make sure that the bell should not touch the body of the bucket. Now place your ear gently on the water surface, you will hear the sound of the ringing bell, thus we can say that sound can travel through water.

The eardrum, or tympanic membrane, is a thin, cone-shaped membrane that separates the external ear from the middle ear in humans, it is like a stretched rubber sheet, sound vibrations make the eardrum vibrate. The ear drum sends vibration to the inner ear and from there signal is send to the brain and in this way we are able to hear the sounds around us.

The eardrum, or tympanic membrane, is a thin, cone-shaped membrane that separates the external ear from the middle ear in humans, it is like a stretched rubber sheet, sound vibrations make the eardrum vibrate. The ear drum sends vibration to the inner ear and from there signal is send to the brain and in this way we are able to hear the sounds around us.

The eardrum, or tympanic membrane, is a thin, cone-shaped membrane that separates the external ear from the middle ear in humans, it is like a stretched rubber sheet, sound vibrations make the eardrum vibrate. The ear drum sends vibration to the inner ear and from there signal is send to the brain and in this way we are able to hear the sounds around us.

The amplitude of a sound wave is the maximum amount by which the instantaneous sound pressure differs from the ambient pressure.

Two cycles of a sine wave showing the amplitude of the pressure variation.The variation of (maximum) amplitude over time is called the envelope of the sound.

Sound waves force the medium particles to vibrate, because of the interaction of the particles present in that medium.

The loudness of sound depends upon the amplitude of vibration, when the amplitude of vibration is large sound produced is large and when amplitude of vibration, is low sound produced is feeble. A baby has low amplitude of vibration in their ear drum thus sound produced by baby is low in compare to adults.

If the frequency of vibration is higher the sound has high pitch and if the frequency of vibration is lower the sound has low pitch.

Whistle will produce sound with higher pitch.If the frequency of vibration is higher the sound has high pitch and if the frequency of vibration is lower the sound has low pitch.

Woman will produce sound with higher pitch.If the frequency of vibration is higher the sound has high pitch and if the frequency of vibration is lower the sound has low pitch.

Range of sound between frequencies 20 to 20,000 Hz is called audible sound as sound between these frequencies is easily audible to human beings. But range of sound less than 20 Hz and more than 20,000 Hz is called in audible sound as sound below 20 Hz and more than 20,000 Hz is not audible to human beings.

Yes, dog can hear sounds of frequencies higher than 20000Hz, because of this ability of dog it is being used by police for investigation purposes.

The ultra sound equipment used for tracking and investigating many medical problems works at frequencies higher than 20000 Hz.

Unpleasant and undesirable sounds are called noise. Example sound produced by horns of vehicles, sound coming from construction sites, sound produced by factories machineries etc.

Presence of excessive or unwanted sounds in the environment is called noise pollution, the main causes of noise pollution is the sound made by horns of vehicles, sound coming from construction sites, sound produced by factories machineries etc. in our home sound produced by television, transistor radio at high volume, airconditioner, coolers, some kitchen appliances like pressure cooker etc. contributes to noise pollution.

In humans, the sound is produced by the voice box or the larynx. It is the part of throat. It moves when we swallow something.

The house that is 50 km away from the factory in a less crowdie place , because house near by the factory will have to face noise pollution because of the industrial machines and also there will be problem of air pollution there.

Noise pollution can lead to number of health related problems like

• Hearing loss
• Loss of sleep
• Hypertension
• Severe headache
• stress

The sound that is pleasing to the ear is called music like sound produced by guitar, piano etc.The sound that is unpleasing to the ear is called noise like sound produced by factories machineries, transport vehicles etc. Yes music can become noise if it is played at high volumes.

The persistence of sound due to repeated reflection and its gradual fading away is known as reverberation of sound.

Echo: Echo is defined as a repetition of sound due to the reflection of original sound by a large and hard obstacle.

The amount of sound energy passing each second through unit area is called the intensity of sound.