- 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.
- 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.