A Laser, or Light Amplification by Stimulated Emission of Radiation, has a high degree of spatial coherence. A high degree of spatial coherence means that the light that is being emitted from the laser is very concentrated making the visible distance that light is traveling much further than that of a standard light source. Another important property of lasers is that they only produce light from a single wavelength. The different wavelengths of light produced from the laser travel at different speeds making some colored lasers have a greater visible distance which they travel. Due to the laser's unique properties, it has gained significant popularity in various fields of science and the military. In the scientific applications, such as lunar laser ranging, the laser is required to travel from one medium to another, thus causing light refraction  This light refraction can be accounted for if the index of refraction is known for both mediums and the incident angle. If a scientific experiment that used a laser, whose light was traveling through different mediums, was to switch their color of laser then their measurements would be different. This would happen because the different frequencies of the lasers which were used. In our experiment, we tested two different colored lasers, red and green, and the amount of refraction they have when their light travels from air to gelatin. In this experiment we hope to show how the different frequencies of lasers travel at different velocities.

Step 1: Research

Snell's law is able to calculate the refracted angle of the light given that you know the two medium's index of refraction and the incidence angle. From the website: http://hyperphysics.phy-astr.gsu.edu/hbase/tables/indrf.html we were able to find the index of refraction of air to be about 1 and the index of refraction for gelatin will vary based on how you make it and the index of refraction that we calculated for our gelatin recipe came out to be about 1.52. We calculated this by shining a laser through our sample and measuring the incidence angle and the refracted angle and then using the equation: (index of refraction of gelatin) = (index of refraction of air) (sine of refracted angle) / (sine of incident angle). 

If you are have any other questions about Snell's law, take a look at this video: 
Nice job. Not sure I understand what you were trying to say about refraction happening twice - the semicircular dish should have one side that is curved such that the beam is normal to the surface and thus does not refract. And the shorter the wavelength - the more refraction - so green should refract more than red. <br>But overall a very interesting lab. You guys are very motivated and it helps make class fun!
Thank you for your inquiry, we must have made an error when writing this instructable as you are right in saying that &quot;refraction does not happen twice.&quot; We will be sure to fix this error. We are glad that you enjoyed our instructable just as much as we did making it :D

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More by christhompson:Changing Refraction Due to Color through Gelatin 
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