thank you for the suggesation before. I'm not sure if I was clear before but, what I'm searching for is like an explination on the definition of physics, not different physics experiments and how to get jobs in physics.

Well - if you are looking simply for a definition - this is the definition according to Websters

"The science of matter and energy and of interactions between the two, grouped in traditional fields such as acoustics, optics, mechanics, thermodynamics, and electromagnetism, as well as in modern extensions including atomic and nuclear physics, cryogenics, solid-state physics, particle physics, and plasma physics."

As mentioned in the previous post I would revisit www.physicsweb.org - I would venture to the tab across the top that is titled "The Best of Physics Web". From there - click on the History tab and then to Physics: Past, Present, Future. There is alot of information about Physics at this site - and to write your essay, you should be able to find lots of info...

You may want to consider starting your essay with the "definition" and then discuss what some Physics see happening in the future....

Physics encompasses so much, that a mere definition will not an essay make. If you are looking for something more concise and at your fingertips, an encyclopedia may be your best option.

Lydia gave some good pointers. Here are some more websites which have in-depth definitions of physics:

Short definition of physics

Another definition.

What do physicists do?

Different branches of pysics and famous scientists