<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2013) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2013) (Learn how and when to remove this template message) </Td> </Tr> <P> A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium . While waves can move over long distances, the movement of the medium of transmission--the material--is limited . Therefore, the oscillating material does not move far from its initial equilibrium position . Mechanical waves transport energy . This energy propagates in the same direction as the wave . Any kind of wave (mechanical or electromagnetic) has a certain energy . Mechanical waves can be produced only in media which possess elasticity and inertia . </P> <P> A mechanical wave requires an initial energy input . Once this initial energy is added, the wave travels through the medium until all its energy is transferred . In contrast, electromagnetic waves require no medium, but can still travel through one . </P>

Waves that need matter to carry energy are called