In addition to a transverse wave, there is also a longitudinal wave. If the transverse wave vibration direction perpendicular to the direction of propagation medium, then the longitudinal wave, the direction of medium vibration parallel to the direction of wave propagation. If you are confused by this explanation, imagine that the vibration of a spring. Note the picture below ...
In the picture above it appears that the direction of vibration parallel to the direction of wave propagation. A series of density and strain propagating along the spring. Density is the area where the coil spring toward each other, while the strain is the region where the coil spring menjahui each other. If you analyze the transversal wave has a pattern of peaks and valleys, the longitudinal wave consists of a pattern of density and strain. Wavelength is the distance between successive density or strain, respectively. What is meant here is the distance from the same two points and a sequence of density or strain (see the example in the picture above).
One example is logitudinal wave of sound waves in air. Air as the medium of sound wave propagation, docked and stretched along the direction of wave propagation in the air. Unlike the water waves or waves of the rope, the sound waves we can not see using the eye. You like to hear a music khan? nah, try to touch the loudspeaker when you're playing the songs. The greater the volume of the song playing, the harder the loudspeaker to vibrate. If observed carefully, the loudspeaker is vibrating back and forth. In this case the loudspeaker serves as a source emits sound waves and sound waves (longitudinal waves) through the medium of air. Concerning the more sound waves will be studied on the subject of its own.
In the above discussion, it was explained that the waves strap gurumuda is an example of a transverse wave, while the examples of longitudinal waves are sound waves. And what about the water wave? not fully water waves transverse waves or longitudinal waves. Water waves are a combination of transverse waves and longitudinal waves.