Vibrations are produced at one end of the metallic container placed in a water tub and in a vacuum tube. Where do you think sound will not be transmitted and why?
Answers
Answer:
Objective
This topic gives an overview of;
Sound
Sound Produced by a Vibrating Body
Sound Produced by Humans
Sound Needs a Medium for Propagation
Sound through our Ears
Sound
How do you come to know that a 'period' is over in your school? You come to know easily that someone is at your door when he knocksor you hear the sound of the doorbell. Most of the time you can make out that someone is approaching you by just hearing the foot steps.
You might have played a game called hide and seek. In this game a person is blind-folded and has to catch the remaining players. How is the blindfolded person able to guess which player is closest to her?
Sound plays an important role in our life. It helps us to communicate with one another. We hear a variety of sounds in our surroundings.
Make a list of sounds you hear in your surroundings. In the music room of your school you hear the sounds made by musical instruments like flute, tabla, harmonium etc.
Sound Produced by a Vibrating Body
Touch the school bell when not in use. Again touch it when producing sound.
Take a metal plate (or a shallow frying pan). Hang it at a convenient place in such a way that it does not touch any wall. Now strike it with a stick. Touch the plate or pan gently with your finger. You will feel the vibrations. Again strike the plate with the stick and hold it tightly with your hands immediately after striking. You will still hear the sound. Touch the plate after it stops producing sound.
Take a rubber band. Put it around the longer side of a pencil box. Insert two pencils between the box and the stretched rubber. Now, pluck the rubber band somewhere in the middle. You will hear sound and the band vibrates.
The to and fro or back and forth motion of an object is termed as vibration. When a tightly stretched band is plucked, it vibrates and produces sound. When it stops vibrating, it does not produce any sound.
We see that a vibrating object produces sound. In some cases, the vibrations are easily visible to us. But in most cases, their amplitude is so small that we cannot see them. However, we can feel them.
Take a hollow coconut shell and make a musical instrument Ektara. You can also make it with the help of an earthen pot. Play this instrument and identify its vibrating part.