Waves All notes provided by Alyse Consiglio of LaBrae Middle School Wave A disturbance that carries energy through matter or space Medium — the matter through which a wave travels. The actual medium is not moving; it just has energy moving through it. Name the Medium Waves on a pond Sound from speakers Water Air Seismic Waves Earth Waves that require a medium are called mechanical waves. Electromagnetic waves do not require a medium. Wave Movement Waves travel from their point of origin equally in all directions. Energy spreads out as it moves away from the point of origin, decreasing in intensity as it spreads. Simple Harmonic Motion A mass on a spring can bounce up and down forever (neglecting friction). This repeating cycle is simple harmonic motion, or SHM. Two Types of Waves Transverse — Particles in medium move perpendicular to the movement of energy Longitudinal — Particles in medium move parallel Surface Waves Move differently because they occur at the boundary between two media. Particles move in circles.