A mechanical wave is a disturbance in matter that transfers energy through the matter. There are three types of mechanical waves: transverse, longitudinal, and surface waves. They differ in how particles of the medium move when the energy of the wave passes through.

Mechanical waves cause oscillations of particles in a solid, liquid or gas and must have a medium to travel through. It is important to remember that all waves transfer energy but they do not transfer matter .

Mechanical waves are an oscillation of matter that transfers energy through a medium. The oscillation does not cause movement of the matter. The mechanical wave will travel until all the initial amount of energy is transferred. Sound waves and ocean waves are examples of mechanical waves.

A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. 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.

These waves can travel through solids, liquids, and gases. P waves can travel through the liquid outer core. An S wave is a different beast. In an S wave, the rock particles slide past one another, undergoing shear — so an S wave is also called a shear wave.

Sound cannot travel through a vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibrations to work in.

S-waves cannot travel through liquids. When they reach the surface they cause horizontal shaking. Liquids don’t have any shear strength and so a shear wave cannot propagate through a liquid. Think of a solid material, like a rock.

P waves twist particles as they pass through materials. S waves cause particles to compress as they pass through materials. Particles are squeezed together and pushed apart by P waves. Particles slide past each other in a crosswise direction as S waves pass through them.

S waves produce vertical and horizontal motion in the ground surface. Particle motion consists of alternating transverse motion. Particle motion is perpendicular to the direction of propagation (transverse).

Because P waves and S waves travel through Earth — not just along its surface — they are also known as “body waves.” This trait makes them useful in a number of ways. For one, scientists can use P waves and S waves to identify where an earthquake began.