How far down does light travel underwater?
Saltwater/ocean if it makes a difference. On a clear day with no waves. If you were scuba diving, how far down can you be and still see well with only the human eye/no flashlights? (seeing other people, plants, and animals)
Also, if you were at the surface and looked down(with goggles on at the top of the water) how far down could you see?
Thanks!
Visible light is scattered by water. Below 100 meters light rarely penetrates even in clear fresh water. The rule is the more stuff in the water the less light penetrates. In the tropics where sunlight comes nearly straight down on to the water surface it penetrates further in. Water is a very dense material, people forget that because water has no sheer strength, and low viscosity. The difference in properties can be shown by the difference in the speed of sound between air and water. In air the speed of sound is close to 600 feet/second, while in water the speed of sound is around 4950 to 5000 feet/second. The density of water seriously impedes electromagnetic waves, because of this greater density.
idk just google it. but i do know that certain colours of light travel further then others. in salt water green travels furtherst and violet travels the least. in fresh water i think all colours go further then in salt water.
References :
it depends on the how clean the water is.
if the ocean was absolutely clear then you should be able to see all the way to the bottom, but its not
so in reality about 100 feet is the limit before you need artificial light
References :
Visible light is scattered by water. Below 100 meters light rarely penetrates even in clear fresh water. The rule is the more stuff in the water the less light penetrates. In the tropics where sunlight comes nearly straight down on to the water surface it penetrates further in. Water is a very dense material, people forget that because water has no sheer strength, and low viscosity. The difference in properties can be shown by the difference in the speed of sound between air and water. In air the speed of sound is close to 600 feet/second, while in water the speed of sound is around 4950 to 5000 feet/second. The density of water seriously impedes electromagnetic waves, because of this greater density.
References :
School
Unlike air particles, light traveling through water quickly loses its color and intensity.
Physics of Light
1. If light, or rather the photons that construct light, existed in a vacuum, they would travel forever in any given direction. In reality, a beam of light experiences multiple disturbances such as absorption, reflection and refraction as it moves through space. This finite distance depends on the situation of the light being transmitted, direction and regions of space through which it will travel.
Short-Term Distance
2. According to the laws of physics, more than half of a light source becomes absorbed within the first three feet of penetrating the water surface. Red, one of the four primary colors that make the lighting spectrum, is the first to be absorbed.
Further Down
3. At 33 feet, the yellow pigment becomes fully absorbed, leaving only 20 percent of the original amount of surface light remaining.
Long-Term Distance
4. As light photons travel through the water, the amount of visible light remaining decreases exponentially. The green color on the light spectrum is next to go at 165 feet, leaving blue light as the final visible source (hence the common hue of underwater photography). By 330 feet only 0.5 percent of the light remains.
Qualities of Light
5. Although different sources of light might give off different percentages of colors within the lighting spectrum–a green and blue dominant fluorescent compared to the sun, for instance–the penetration level and consistency remains the same.
References :
It depends on the clarity of the water, and the wavelength of light.
The longer wavelength red and yellow parts of the spectrum are more readily absorbed by water, and a red object would appear black (because the red light reflected from it is absorbed) even a few metres down.
At a depth of about 200 metres, most of the blue light is absorbed, and you’d need artificial light.
Below about 2000 metres, the water is pitch black, and it is known as the aphotic (‘without light’) zone.
Here’s an interesting site:
http://www.mbgnet.net/salt/oceans/zone.htm
References :
as above