Types of Waves

"A **wave** is a disturbance that travels or *propagates* from the place where it was created. Waves transfer energy from one place to another, but they do not necessarily transfer any mass." "Sound and water waves are **mechanical waves**; meaning, they require a medium to travel through. The **medium** may be a solid, a liquid, or a gas, and the speed of the wave depends on the material properties of the medium through which it is traveling. However, light is not a mechanical wave; it can travel through a vacuum such as the empty parts of outer space." "A **pulse wave** is a sudden disturbance in which only one wave or a few waves are generated, such as in the example of the pebble. ... A **periodic wave** repeats the same oscillation for several cycles, such as in the case of the wave pool, and is associated with simple harmonic motion." "A **transverse wave** propagates so that the disturbance is perpendicular to the direction of propagation. ... In contrast, in a **longitudinal wave**, the disturbance is parallel to the direction of propagation." "The longitudinal waves in an earthquake are called pressure or P-waves, and the transverse waves are called shear or S-waves."