Below are some urls that direct you to video about osmosis to get a better understanding of it
http://www.youtube.com/watch?v=sdiJtDRJQEc
http://www.youtube.com/watch?v=aubZU0iWtgI
http://www.youtube.com/watch?v=sdiJtDRJQEc
http://www.youtube.com/watch?v=aubZU0iWtgI