What is science?

Science is the concerted human effort to understand, or to understand better, the history of the natural world and how the natural world works, with observable physical evidence as the basis of that understanding¹. It is done through observation of natural phenomena, and/or through experimentation that tries to simulate natural processes under controlled conditions.

By http://www.gly.uga.edu/railsback/1122science2.html

Finally in this video you can watch more about what is science
http://www.youtube.com/watch?v=_JjT_6_mX1k