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Lab Report

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  Vision is the most important sense that the human possesses. It not only helps

you to observe your surroundings, but it also allows you to read. However,

when the eye is underwater it sees everything differently. When you see

underwater you can not see anything clearly, unless if you have a scuba mask

on. If you do have a scuba mask on it affects your eyes in a different way. You

see everything around 25 percent closer than it really is. To understand why it

is different between water and air you have to know about three terms. These

three important terms are refraction, scatter, and absorption.


The first of these terms is refraction. Refraction could be defined as light that

passes through one density to another density, and during this process the light

bends. Refraction occurs when the light makes contact with the mask, which

has air in it. This causes any underwater object to appear larger than it really is.

This also makes all objects underwater 25 percent closer than it really is. It

also has the opposite effect on underwater objects that are far away. When an

object is far away than the object appears to the diver farther away than it

really is. This perception happens to everyone, unless people train themselves

to see properly underwater.


The second term that you have to understand is scatter. Scatter is when

individual light photons come in contact with particles in the water, which

causes the photons to be turned into another direction. This occurs in the air,

but not as much as it occurs in the water. It not only happens more in the

water but it also has a greater effect too. Scatter underwater interferes with

vision because it reduces the contrast between an object underwater. This is the

main reason why it is so much harder to see in the water than it is to see in the

air. Scatter is one term that you have to know because it explains why it is

harder to see underwater.


The last and most important term that you have to know is absorption. From

the term alone it pretty much explains itself. Light is absorbed when it passes

through the water, and by the time it reaches an object it already lost most of

the light. This process occurs even in the clearest of water, and that is why it is

always hard to see when you get deep in the water. In the clear waters the

order of colors that are being absorbed are red, orange, yellow, green, and

then blue. In other waters it depends what the water contains. If it has plankton

than it would filter out blue and violet, and this list would go on and on.


If you ever scuba dive underwater you have to know the terms refraction,

scatter, and absorption. You have to know these terms because otherwise you

would not understand why you couldn't see that well underwater. In

conclusion, there are different factors that make vision underwater different

than it is in the air.

 

Diagrams

Eye

Vision Paths Underwater

Pictures from http://www.cosmic-wrench.com/jeff/photos/ocean2s.jpg

 Title Page

 Background Information

Lab Report

 Analytic Essay

 Display of Results

 Diagram

 Photographs

 Links

 Animation

 Enhancements

 Bibliography

 St. Matthew's Deep Website