https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5 Made with mirth en-us 2020-12-08 13:20:02 UTC 2026-03-14 00:52:35 UTC hello@padlet.com ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/997959404 2020-12-08 13:32:19 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/997959404 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998253424 When a body is set into vibration, it vibrates with a particular frequency of its own . This frequency is its natural frequency.
  Frequency  (f) =    No. of oscillations( n) /  Time  (t)

]]> 2020-12-08 14:39:12 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998253424 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998272372   
What are the reasons for the differences in the natural frequencies of  different objects?

]]> 2020-12-08 14:43:12 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998272372 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998274586 2020-12-08 14:43:41 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998274586 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998277309 Observe figure 1. 
Do all pipes make sounds of the same kind? 
What difference do you  observe between the pipes? 
Make an instrument using  PVC pipes instead of metal pipes as shown in fig.1  and try to produce sounds. Is the sound the same as the one produced by metal pipes? What could be the reason for the  change in sound? 
Factors that influence the natural frequency of a body 
● Nature of the body
● Length
● Surface area
● Tension
● Area of cross section

]]> 2020-12-08 14:44:16 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998277309 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998305721 https://youtu.be/FznldJHCbBU]]> 2020-12-08 14:50:17 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998305721 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998318492 The sharpness  of the sound heard is the pitch. It depends on the frequency of sound.]]> 2020-12-08 14:52:47 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998318492 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998344290 2020-12-08 14:55:26 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998344290 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998346458 Loudness is the measure of audibility of a person . This depends mainly on the amplitude of  vibration and the sensory ability of the ear. The unit of loudness is decibel ( dB). This is measured using a device named decibel meter.]]> 2020-12-08 14:55:52 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998346458 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998348784 2020-12-08 14:56:20 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998348784 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998363049 How does sound from different sound sources that reach us? 
Let’s see an experiment.

]]> 2020-12-08 14:59:06 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998363049 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998365056 https://youtu.be/jMEgzsmJdmQ]]> 2020-12-08 14:59:29 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998365056 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998366936 What do you observe?]]> 2020-12-08 14:59:51 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998366936 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998369369 A medium is necessary for sound to travel]]> 2020-12-08 15:00:20 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998369369 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998371801 Is it only through air that sound travels? Let’s see.]]> 2020-12-08 15:00:51 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998371801 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998384340 https://youtu.be/AxNdr0Bcx20]]> 2020-12-08 15:03:13 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998384340 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998386417 You would have understood  that sound can propagate not only through air but also through other materials .]]> 2020-12-08 15:03:34 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998386417 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998423554 2020-12-08 15:10:21 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998423554 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998426238 You might  have understood that sound is produced due to vibration and  requires a medium for its propagation. But how do we sense sound? Which sense organ helps us here?  ]]> 2020-12-08 15:10:51 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998426238 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998428347 2020-12-08 15:11:15 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998428347 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998430671 How should we approach people with impaired hearing ?]]> 2020-12-08 15:11:42 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998430671 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998432876 https://youtu.be/eQEaiZ2j9oc]]> 2020-12-08 15:12:08 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998432876 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998435775 2020-12-08 15:12:44 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998435775 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998443248 Can a person with normal audibility hear all sounds? ]]> 2020-12-08 15:14:10 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998443248 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998445178 Sounds having frequencies greater than 100000 Hz occur in nature due to the vibration of bodies. We cannot hear sounds of all frequencies. It means there is a limit to the frequency of sound that can be heard by human beings. For a person with normal hearing capacity, the lower limit of audibility is about 20 Hz and the higher limit of audibility is about 20,000 Hz . This limit varies from person to person.]]> 2020-12-08 15:14:32 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998445178 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998461137 2020-12-08 15:17:39 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998461137 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998463718 2020-12-08 15:18:07 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998463718 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998466556
Sounds with frequency of less than 20 Hz are called  infrasonics  and those with a frequency greater than 20000 Hz are ultrasonics.

]]> 2020-12-08 15:18:41 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998466556 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998469182 2020-12-08 15:19:12 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998469182 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998500757 ● Ultrasonic waves are used in the instrument SONAR ( Sound Navigation And Ranging )  to measure the depth of the ocean.
● Ultrasonic waves are also used in the medical field for diagnosis and treatment.

]]> 2020-12-08 15:25:11 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998500757 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998503224 https://youtu.be/yZty_W8ySng]]> 2020-12-08 15:25:41 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998503224 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998514777 2020-12-08 15:27:59 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998514777 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998517518 Production of sound in a manner unhealthy to human being is noise pollution]]> 2020-12-08 15:28:31 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998517518 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998523139 REDUCING NOISE POLLUTION 
● Use of air horns in vehicles is prohibited by law.
● Box type loudspeakers must be used in place of horn type loud speakers . 
● Ensures that silencers in vehicles work properly.
● Plant as many as trees as possible to minimize noise pollution . Trees can reduce loudness of sound by absorbing sound energy.
● Loudspeakers should not be used in public places before 6 am and after 10 pm.
● Do not make sounds above 50 dB in the premises of hospitals , educational institutions etc.

]]> 2020-12-08 15:29:34 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998523139 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998529859 2020-12-08 15:30:46 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998529859 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998553330 2020-12-08 15:35:00 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998553330 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998581294 1. Choose the correct answer 
    Sound can travel through
(a) Gases only     (b) solids only     (c) gases only   (d)  solids , liquids , gases 
2. Which of the following voices is likely to have minimum frequency?
          (a)  Baby girl      (b) Baby boy   (c) A man   (d) A woman
3. The two kinds of sounds that we cannot hear are -------- and -----------.
4.  The sound is a form of ----------that is produced when objects vibrate.
5. Name two  musical instruments which produce sound by vibrating strings ? 
6. A simple pendulum makes 10 oscillations in 20 seconds. What is the frequency of its oscillation ?
7. We have learnt that vibration is necessary for producing sound. Explain why the sound produced by every vibrating body cannot be heard by us?
8. list  three  sources of noise pollution in your locality.

]]> 2020-12-08 15:40:17 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998581294 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998613601 Hope you noticed the child’s soliloquy …………
Have you ever thought how the mosquito makes sound while flying?
Sound is a form of energy which is familiar to us and is used for communication.
How is sound produced ?
How does it reaches our ears?
Why are all sounds not heard alike? 
Let’s examine.

]]> 2020-12-08 15:46:25 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998613601 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998637358 https://youtu.be/IrNaRnpozy0]]> 2020-12-08 15:50:58 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998637358 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998661189 2020-12-08 15:55:39 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998661189 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998671124 MAN- MADE  SOURCES OF SOUND]]> 2020-12-08 15:57:35 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998671124 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998674326 2020-12-08 15:58:13 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998674326 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998675760 NATURAL  SOURCES OF SOUND]]> 2020-12-08 15:58:29 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998675760 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998679046 2020-12-08 15:59:08 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998679046 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998682214 How is sound produced from materials ? let’s see]]> 2020-12-08 15:59:45 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998682214 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998684898 https://youtu.be/-J9HhdgV1cY]]> 2020-12-08 16:00:18 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998684898 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998687723  
Sound is produced by the vibration of objects.
The  sound  produced from the source of sound would be the sum total of the vibration of the various parts related to the source. However , every sound source has a main  vibrating part to produce sound .

]]> 2020-12-08 16:00:52 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998687723 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998691994 MUSICAL INSTRUMENTS AND THEIR VIBRATING PARTS]]> 2020-12-08 16:01:43 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998691994 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998696821 2020-12-08 16:02:39 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998696821 ssinjurajsnvk https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998699546 Try to listen to sounds by plucking the different strings of a violin . Are the sounds emitted from all the strings similar ? 
What may be the reason for the difference in the sounds produced by chenda and edakka?
Let's take a look at  some properties that bring in differences in sounds produced by different sources of  sound.

]]> 2020-12-08 16:03:09 UTC https://padlet.com/ssinjurajsnvk/6b6r3430wqdkd3g5/wish/998699546