

Similarly, the amplitude can be measured from the rest position to the trough position. In a sense, the amplitude is the distance from rest to crest. The amplitude of a wave refers to the maximum amount of displacement of a particle on the medium from its rest position. The wave shown above can be described by a variety of properties. The trough of a wave is the point on the medium that exhibits the maximum amount of negative or downward displacement from the rest position. Points C and J on the diagram represent the troughs of this wave. The crest of a wave is the point on the medium that exhibits the maximum amount of positive or upward displacement from the rest position. Points A, E and H on the diagram represent the crests of this wave. At any given moment in time, a particle on the medium could be above or below the rest position. Once a disturbance is introduced into the string, the particles of the string begin to vibrate upwards and downwards. This is the position that the string would assume if there were no disturbance moving through it. The dashed line drawn through the center of the diagram represents the equilibrium or rest position of the string. If a snapshot of such a transverse wave could be taken so as to freeze the shape of the rope in time, then it would look like the following diagram. A transverse wave can be created in a rope if the rope is stretched out horizontally and the end is vibrated back-and-forth in a vertical direction. A transverse wave is a wave in which the particles of the medium are displaced in a direction perpendicular to the direction of energy transport.
