Find the fastest path from Point C to Point D!
The Velocity of Light in Medium 1 (top) is not the same as the velocity in Medium 2 (bottom)!

Instructions:
1) Choose the position of Point C in Medium 1 and the position of Point D in Medium 2.
2) Choose the velocity of light in Medium 1 (c_1) and in Medium 2 (c_2).
3) Slide the Point E along the surface until you find the fastest Total Time.
4) Check the Box "Show Lot and Angles".
5) Check the new Box and take a look at the calcualtions of Snell. What condition do you discover for the fastest path?
6) Move the Point E, again, and observe what happens with the angles and the calculations of Snell.
7) Explore other positions for the Points C and D and find the fastest path.
8) Explore other velocities c_1 and c_2 and find the fastest path.