Eye Color and Dilation Science Projects
If you want to explore the genetic foundation of eye functioning, consider a science project on eye color and dilation. Although only a few possible projects are possible without an advanced degree, each project grants you the ability to draw a number of conclusions. For example, if a blue-eyed person's pupils dilate and constrict quicker than a dark-eyed person's, you might draw the conclusion that, over time, people with light eyes may have experienced more sudden lighting changes than their dark-eyed counterparts.
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The Iris
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The colored part of the eye is known as the iris. The colors blue, green and brown are familiar eye colors, although potential eye colors also include gray, yellow, hazel and black. Scientists believe that two genes determine the eye's amount and type of pigment; in turn, the pigment determines visible color.
A project about eye color and dilation must explore the biological history of people to determine if the genetic causes for eye color relate to the genetic roots of pupil dilation.
The Pupil
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The pupil (the dark spot in the center of the eye) constricts and expands, i.e., dilates, depending on the amount of light coming in. During dilation, the pupil opens up and takes in more surrounding light. It closes up during constriction, restricting the amount of light entering it from a bright area.
Interestingly, dilation occurs for other reasons, as well, including exposure to chemicals when a person is excited, happy, or recognizes something that was previously unrecognized, such as a familiar face in a crowded room.
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Dilation Size
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Perform a project relating to the dilation of the pupil to eye color. To do this, you must measure the size of dilation, as it regards the total size of the iris and pupil combined.
Place a high mega-pixel, night-vision camera on a sturdy table. Experiment with four different types of light: bright light, average light, dim light and no light. Under each light condition, instruct your subject (use at least three subjects for each eye color) to sit across from the camera, looking directly into the camera lens. Take a picture, without the flash, in each light. In the darkest light setting, use night vision to detect the size of the pupil. Print out all of the different images and determine the size of the pupil in relation to the size of the iris. At the end, draw a conclusion about the size of pupil dilation and its dependence on the color of the iris.
At advanced levels, focus your dilation project on dilation chemical, rather than illumination-based, causes for pupil dilation.
Dilation Speed
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Measure dilation speed for differently colored irises using a video camera with the capability of frame-by-frame review.
Place the video camera on a table and instruct your subject (use at least three different subjects for each eye color) to sit across from the video camera, looking into the lens. Turn off the light. With the video camera recording, turn on the light in the room. Do this several times for each subject. Review the videotapes and record the exact number of frames it took for the pupil to constrict and dilate for each subject. Compare the different iris colors with each other and record any trends.
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References
- Photo Credit eye image by Pali A from Fotolia.com
