ABSTRACT
Energy is one of the more important concepts in science. It appears in many forms, including mechanical energy, thermal energy, electromagnetic energy, chemical energy, and nuclear energy. Wherever and whenever anything happens, like the explosion of a distant sun or the falling of a golden leaf from a tree in autumn, a change in some form of energy is involved. In spite of our familiarity with the concept of energy, few of us can dene it properly. What is energy? Can we measure it? Can we touch it?
