Rubbing up the right way!
Rubbing up the right way!
![](http://admin.indiaenvironmentportal.org.in/files/images/20020515/47.jpg)
when you move a piece of chalk on a blackboard, a nerve tingling screeching sound is produced. This is an example of the
Publication Date:
14/05/2002
![]() |
when you move a piece of chalk on a blackboard, a nerve tingling screeching sound is produced. This is an example of the