Seeing vibrations

We can directly see things vibrating or we can feel the vibrations by touching things.

Let us do the following activity to see vibrations when we make a sound.

Activity: Dancing rings on the base of the cup

Materials Required:
1. One paper cup
2. One straw                                                                           

Procedure:  
1. Cut a straw to get rings (as shown in the figure)
2. Hold a paper cup in an inverted position
3. Now put the rings on the base of the paper cup                                  Image 1.6: Straw rings
4. Hold the cup with both hands close to the mouth and shout into it.    

Why do the straw rings jump around?

To feel the vibrations, hold the paper cup inverted and shout into it. Ask your friend to touch the base of the cup while you are shouting into it.
 
You can also feel the vibration of your voice. Place your fingers gently against your throat and say ‘aaaahhh’ or ‘hmmmm’ or ‘hooooo’ or any sound and say it a little loudly.