What form of energy do you use to produce sound ?

How do we produce sound ?

We know that the sound is a form of energy. So, the large amount of energy produced due to the sound pollution in cosmopolitan cities can be used to our day to day needs of energy. It also helps us to protect biodiversity in urban areas”. Do you agree with this statement? Collect information on this and write a report.

What do you mean by a hole ? How is it produced ?

What is roasting? when do you use it?