Exploring Birefringence

Follow the steps below to explore birefringence, then answer the questions for this activity:

1) Go to EMANIM website
2) Click the checkbox to 'turn on' Wave 2
3) Click the checkbox to 'turn on' Wave 1 + Wave 2
4) Increase the amplitude of Wave 2 to 5 (this now matches the amplitude of Wave 1)
5) Scroll down and click the checkbox to 'turn off' Components
6) Change the phase difference for Wave 2 to 90 (this is in degrees) -- observe the superposition of waves
7) Click the checkbox to 'turn on' a Material -- note that an orange parallelepiped appears to indicate the material volume
8) Increase the length of the material to 20
9) Change the index of refraction for Wave 2 to produce a GIF similar to the one below