Energy is present whenever there are moving objects, sound, light, or heat. The faster a given object is moving, the more energy it possesses. When objects collide, energy can be trans- ferred from one object to another causing the objects’ motions to change. Energy can also be transferred from place to place by electrical currents, heat, sound, or light. Devices can be de- signed to convert energy from one form to another.

Waves are regular patterns of motion that transfer energy and have properties such as ampli- tude (height of the wave) and wavelength (spacing between wave peaks). Waves in water can be directly observed. Light waves cause objects to be seen when light reflected from objects enters the eye. Humans use waves and other patterns to transfer information.