ABSTRACT
Models for the Behavior of Light For thousands of years people have wondered what light really is, and have tried to construct models predicting its behavior. In the seventeenth century Sir Isaac Newton put forward the concept of “energy,” and used it as a fundamental property of objects in motion. He also ascribed it to such things as unwinding springs, burning gases, sound and-important in our context-light. Not everyone agreed with him at the time. But today, when we operate switches, drill teeth, and even weld metal with light beams, there is no longer any doubt.
