LIGHT and COLOR image courtesy of http://thedivingblog.com/colors-underwater/ As you descend underwater, the amount of light that penetrates the water decreases. Visible light can be broken into 7 broad color categories. Red, orange, yellow, green, blue, and violet. Underwater, red light starts to go at 1 meter and is gone by 5 meters. Orange light starts to go at 5 and is gone by 16 meters. Yellow starts to go at 22 and is gone by 30. Green starts to go at 50 and is gone by 76 meters, and violet starts to go at 4.5 meters and is gone by 30. Blue light lasts the longest until 80 meters, and after that no visible light remains. Water absorbs the visible light, starting with the weakest wavelengths (red, orange, yellow violet) and ending with the stronger wavelengths. Water also diffuses light, which is why light only reaches to certain depths. On top of messing with color, water also messes with how large things appear. As light passes from air to water, it bends. This is because water is more dense, so the speed the light is traveling decreases. This is called light refraction, and it causes objects to appear 33% larger underwater. BACK     NEXT PAGE