I came across this video on youtube, for a more clear view on supply and demand, i thought it would be helpful to other community members as well. So, i decided to share it here with you guys .
https://www.youtube.com/watch?feature=player_embedded&v=PEMkfgrifDw
https://www.youtube.com/watch?feature=player_embedded&v=PEMkfgrifDw