SNELL'S LAW LAB
 

The general purpose of this lab is to determine whether the speed of light changes in different types, flavors or brands of soda pop using Snell's Law. (Work with your group to determine a SPECIFIC purpose)

Towards that end, please work with your colleagues to design a lab using Snell's Law of refraction.

PLEASE NOTE: I have hand-held lasters in red, blue and green. You are welcome to use any ONE of those. Please make sure you return them when you are done. (Keep in mind the goal is to see if the speed of light changes between types or brands of soda, NOT to investigate the different colors of laser light so the type of laser is a CONTROL variable in this case)

Also, make sure to choose both a soda AND a laser color that have a high enough contrast for you to be able to see the light ray as it bends from air to liquid (soda).

You are welcome to use any size of glass beaker or flask (or whatever) that I have put out for you.

To do these investigations, you'll need to measure the angle of incidence and the angle of refraction which presents a number of unique problems for you to address BEFORE you get started!

I'll give you a VERY Big hint: Both Android & Apple have numerous apps that allow you to use your camera phone to measure angles. Work together with your crew to find the best app.

Here's a review of the math you'll need:

NOTE that the subscript 1 is the incident angle and the subscript 2 is the angle of refraction

  • Snell's Law (sometimes called 'The law of refraction'):

n1sin Θ1 = n2sinΘ2

  • The ratio of the velocity of light in air to the velocity of light in another tranluscent (allows light to pass through) medium is equal to the INVERSE of the ratio of the index of refraction in air to the index of refraction of that second medium (hopefully you drived that relationship in Optics 03 and my review of that occurs in Optios 04):

v1/v2 = n2/n1

  • The ratio of the sine of the angle of refraction to the sine of the angle of incidence is equal to the ratio of the speed of light in the second medium to the speed of light in air

sin Θ2/sinΘ1 = v2/v1

 

Use a laser pointer or other hand-held-laser-like thingy to shine beam of light from air into each of the types, flavors or brands of soda that you'll be using and measure the angles of incidence and the angle of refraction for each.