Sound waves refer to a type of mechanical wave that is created by vibrations or disturbances in an elastic material, such as air, water, or solid objects. These waves propagate through the medium by compressing and decompressing the particles within it, causing them to oscillate back and forth. The direction, amplitude, frequency, and speed of sound waves can vary depending on the properties of the medium they are traveling through. Sound waves are responsible for the sensation of hearing in humans and other animals, as well as for various other phenomena such as echoes, reverberations, and Doppler effects.