A region where the coils are spread apart, thus maximizing the distance between coils, is known as a rarefaction. A compression is a point on a medium through which a longitudinal wave is traveling that has the maximum density. A region where the coils are pressed together in a small amount of space is known as a compression. If a snapshot of such a longitudinal wave could be taken so as to freeze the shape of the slinky in time, then it would look like the following diagram.īecause the coils of the slinky are vibrating longitudinally, there are regions where they become pressed together and other regions where they are spread apart. A longitudinal wave can be created in a slinky if the slinky is stretched out horizontally and the end coil is vibrated back-and-forth in a horizontal direction. Any one of these distance measurements would suffice in determining the wavelength of this wave.Ī longitudinal wave is a wave in which the particles of the medium are displaced in a direction parallel to the direction of energy transport. In the diagram above, the wavelength is the horizontal distance from A to E, or the horizontal distance from B to F, or the horizontal distance from D to G, or the horizontal distance from E to H. In fact, the wavelength of a wave can be measured as the distance from a point on a wave to the corresponding point on the next cycle of the wave. The wavelength can be measured as the distance from crest to crest or from trough to trough. And the length of one such spatial repetition (known as a wave cycle) is the wavelength. It repeats itself in a periodic and regular fashion over both time and space. If you were to trace your finger across the wave in the diagram above, you would notice that your finger repeats its path. The wavelength of a wave is simply the length of one complete wave cycle. The wavelength is another property of a wave that is portrayed in the diagram above. In the diagram above, the amplitude could be measured as the distance of a line segment that is perpendicular to the rest position and extends vertically upward from the rest position to point A. 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.

Horizontal compression definition