# Calculating the Speed of Light using Snell's Law

1. Mar 8, 2010

### AlbertRogers1

1. The problem statement, all variables and given/known data
Hi, I am currently working on science fair physics project which involves measuring speeds of light passing through several substances using a green laser. (please note, I am in 8th grade and have not studied trigonomtry.) We already have our angles on graph paper with a normal but we are confused to exactly caluculate the speed of light using Snell's Law. We are wondering if it was possible that someone could clarify for us in simple terms how to use the formula belonging that Snell's Law to calculate the speed of light.
Here are the angles which were formed by the normal line when we shined the laser beam through a square tupaware, with the same point of entry every time! Here are the angles.
The first substance we used was oil:
The angle before entering the substance was: 25 degrees
The angle after the beam enters the substance was: 16 degrees

The second substance was Steak Marinade mixed with water
The angle before entering the substance was: 25 degrees
The angle after the beam enters the substance was:23 degrees

The third substance was blueberry Fuze (a type of drink)
The angle before entering the substance was: 25 degrees
The angle after the beam enters the substance was:22 degrees

2. Relevant equations

sin(b)=A*sin(a)/B
or:
b = arcsin[A*sin(a)/B]

3. The attempt at a solution

Please. I am in 8th grade doing an 11th grade level project in order to get an A+. The project has been going very smoothly until the math kicks in. Given the information above, please help me set up the math equation!!!!!!!!!
THANKS
-Albert

Last edited: Mar 8, 2010
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