In physics, a wave is a disturbance or variation that travels through space and matter, transferring energy from one place to another. Waves can be classified as mechanical or electromagnetic, and they can take many forms, such as sound waves, light waves, water waves, seismic waves, and more. Waves are characterized by their amplitude, wavelength, frequency, and speed, and they exhibit various properties, such as reflection, refraction, diffraction, interference, and polarization. Waves are a fundamental concept in physics and are used to explain many phenomena in the natural world, from the behavior of particles at the quantum level to the movement of galaxies in the cosmos.