This topic from General Science and contain the complete detail about the topic..
 
This pdf covers the topic from Class 6 to 12 of the samacheer book (SCERT).
 
For the topic video class, check
https://www.youtube.com/watch?v=QyUghrhZoZU&list=PL5mz0KRAIPbTdlCOMX7G7TUcliWGIzXNu