Sound

Sound:

• Sound is a very important part of our lives.
• Sound is basically the energy made up of vibrations caused by any object or medium.
• To and fro motion of any object is termed as vibration.
• The greater is the amplitude the more is the vibration and the louder is the sound.
• When we speak our vocal cords or larynx  vibrate to produce a sound.
• Two vocal cords are stretched across the voice box or larynx in a way that it leaves a narrow slit between them for the passage of air.
• Then the lungs force air through the slit, and the vocal cords vibrate producing a sound.
• Men have larger vocal cords then women,
• Whereas children have a very short vocal cord.
• That is why all of them have different voices.

Does Sound Needs A Medium To Travel?

• Yes, the sound needs a medium to travel.
• Sound cannot travel through Vacuum.
• Sound can travel through solid, liquid and gas.
• We are able to hear the sound with the help of our ears.
• The outer part of our ear collects the sound.
• Then the sound travels down a canal.
• At the end of the canal there is a thin stretched membrane which is called the eardrum.
• Sound vibrations makes the eardrum vibrate.
• And then the eardrum send those vibrations to the inner ear.
• The vibrations from the inner ear is received by our  brain.
• That’s how we are able to hear.
•  Our eardrum is very important to us.
• If the eardrum gets damaged we may become deaf.

What is an Amplitude:

• The maximum extent of a vibration or oscillation measured from the position of equilibrium is known as amplitude.
• It measures how loud or soft a sound is.

What is Frequency?

• The number of oscillations per second is termed as frequency .
• The symbol of frequency is hertz (Hz).
• Amplitude and Frequency are two important properties of any sound.
• We can differentiate between sounds with the help of it’s amplitude and frequency.

What is Time Period?

• The time taken by a pendulum to complete one oscillation is it’s Time Period.
• The unit of Time Period is Seconds (s).
• Frequency and Time Period are inversely proportional to each other.
• As frequency increases , the time period decreases.

Loudness Of A Sound?

• Loudness of a sound is proportional to the square of the amplitude of the vibration producing the sound.
• The loudness of a sound depends on it’s amplitude.
• If the amplitude is large, the sound produced is loud and vice-versa.

Pitch Of A Sound?

• The loudness and the softness of a sound is called Pitch of a sound.
• If the frequency of a vibration is higher, the pitch produced is loud.
• If the frequency of a vibration is lower , the pitch produced is low.

Audible and Inaudible Sound:

• The vibration of a sound which is in between 20HZ AND 20,000hZ is an audible sound.
• The vibration lower then 20Hz cannot be detected by human ear so it is termed as Inaudible Sound.
• Dogs can hear a sound above 20,000Hz.

What is Noise?

• Unpleasant sound which a human ear can’t tolerate is considered as Noise.

Noise Pollution:

• Presence of excessive and unwanted sound  in our environment is called Noise Pollution.
• Major causes of Noise Pollution are horns of Vehicles, burning of crackers, loudspeakers etc..
• Presence of excessive noise in our surrounding is bad for our health
• As it causes headaches , High blood pressure, irregular sleep patterns etc..
• A person can also have temporary or permanent impairment of hearing if exposed to loud sound.

How We Can Control Noise Pollution:

• Silencing devices should be installed in vehicles .
• Factories or various industries should be build up away from residential areas.
• TV or speakers should be at at low volume by which others don’t get disturbed.
• We should plant as many trees as we can to reduce the power of the sound.
• We should cover our windows through curtains or shut the door to minimise the effect of sound.