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Photo by Malene Thyssen.


1. OCEANOGRAPHY. A raised ridge of water that moves across the surface of an ocean or a lake. Waves are caused by the winds, currents or tidal forces, or combinations of these. 2. PHYSICS. A vibrating motion or a rapidly changing electromagnetic field that passes through a medium such as air or water or through space without causing any permanent change in the medium. Sound waves can travel through gases, liquids, or solids. Light, other electromagnetic radiation, and heat can travel through these and through a vacuum. 3. GEOLOGY. Shaking movements of the ground, called seismic waves, are caused by earthquakes or explosions.