You must have read about Friction in books, but now with Extramarks start learning with the help of videos and animations. These videos are prepared for the students to have a better understanding of the concept. The video for the concept of Increasing and Reducing Friction for class 6 to class 8 is now available at the Extramarks website. To get access to these videos get yourself registered with Extramarks.
https://www.youtube.com/watch?v=M0W04bUSvAc