Demonstrations of both traveling and standing waves in a uniform line of cars connected by springs on an air track are described, the crucial point being the special mass and damping necessary for the last car in the case of traveling waves. The theory of the motion of the cars under various circumstances pertaining to the demonstrations is presented, and procedural details are described. A scheme is outlined for using the wave demonstrations in an introductory course, and another, simple demonstration is mentioned. A demonstration of the localized mode associated with a light impurity car is described.