Hearing

Vision and hearing are two of the major ways in which most humans gain information about the outside world. The principles of sound are similar to those of light in that both sound and light travel as waves. With light, the amplitude of the wave corresponds to brightness, and with sound, amplitude corresponds to volume, or loudness. The length of light waves determines its hue, or color; while the length of sound waves determines its pitch. The outer ear, ossicles of the middle ear, and cochlea of the inner ear all help sense sound.