The amplitude of the wave (the actual direction of the waving) is in a direction that is perpendicular to the surface of the water. When the wave has a positive amplitude, the color is white, when the...The amplitude of the wave (the actual direction of the waving) is in a direction that is perpendicular to the surface of the water. When the wave has a positive amplitude, the color is white, when the amplitude is zero the color is light gray, and when the amplitude is negative the color is black.