Mount the laser and make sure it is stable 4. If the sides are not flat it can bend. Make gelatin according to box instructions and pour water in a container.
Use Snells law to determine the speed of light through the gelatin.
Shoot the laser at the Gelatin at 45 degrees in respect to the normal and after finding the refractive angle use Snells Law and the Formula for Index of Refraction to calculate the Speed of Light within the Gelatin. They defined the meter as the distance light traveled in vacuum for 1299792458 of a second such that the speed of light in a vacuum is drum roll 299792458 ms or 299792458 kms. First use Snells law refer to the Background tab to calculate the index of refraction of the gelatin and then apply the definition of index of refraction to find the speed of light in the medium. Fortes III Fatima F.