Entropy can be thought of as a measurement of the disorder of
a system. All systems have a tendency to move from ordered states
to less ordered states. Chuck provided an example with the box
of marbles and, as anyone knows, a room in a home will become
disordered over time and work has to be done to reorganize it
and put things back in their places. But entropy has a deeper
meaning with respect to energy. Whenever energy freely transforms
from one form to another, it moves from easily accessible forms
to less usable forms like heat.
If you think back to the example that you saw in an earlier show about the boxes that the mother was looking for in her child's room, we realize that the number of boxes was always the same. When all the boxes were in the chest, boxesenergywere very organized; however, with each example it became more difficult for the mother to find and account for the boxes. The boxes and the room were more disordered with each situation. She could, of course, find all the boxes and bring them back to where they started in the chest by doing some work.
So, while we can decrease the entropy of a specific location or a specific object, somewhere else in the universe the entropy will increase.