ABSTRACT
A smart material has the ability to change shape or other properties in response to stimuli such as heat, electric field, light, etc. Such behavior is useful for making devices without individual moving components. For example, a motor usually has wire windings, magnets, and gears. Materials that have these functions built in convert the stimulus directly to mechanical energy, so they can be made much smaller and more reliable. Indeed, the materials that Bell used to make musical tones from light pulses is an example of a smart material (see Chapter 1). In his experiments, the acoustical waves are generated in the material when energy is absorbed from a light beam.
