1. Happy Friday!!! 3-18-16 Get ready for warm up # 2 Quiz postponed Get out a paper to take notes on Title these notes “Light and Polarization” You will turn these in for a grade at the end of class

2. Warm up # 2 Light travels through a liquid at 2.25 x 10 8 m/s. What is it’s index of refraction?

3. Notes- light and polarization Light is a transverse wave NOT a compression wave

4. Light travels from all directions

5. Light can be “polarized” Polarized light waves are light waves in which the vibrations occur in a single plane.

6. “Polarization” occurs when a transverse wave is able to pass through a material only if it is oscillating in a certain direction.

7. Light polarization Unpolarized polarized

8. In general, one filter will block 50% of the light that tries to pass through it. A 2 nd filter, placed after the first, can block anywhere from 0% additional, or ALL of the remaining light. It depends on how it is rotated relative to the first filter. NOTE: Only transverse waves can be polarized.

9. Each fence represents a “polarizing filter”. If the two filters are both vertical, then any wave that makes it past the first fence, will also make it through the 2 nd fence.

10. If the two “filters” are aligned perpendicularly, then any wave that gets past the 1 st filter will NOT be able to make it through the 2 nd filter.

11. 3-D movie glasses are actually polarizing filters. Try this experiment next time you are at a 3-D movie: Overlap one filter over another. Rotate if necessary. The combination should block the light!

12. polarized light polarization 2

13. Old-style 3D movies used Red & Blue filters:

15. A polarizing filter is often used in photography to reduce glare from smooth surfaces:

18. This picture was taken with a polarizing filter. It allows us to see “strain” on the eyeglasses.

20. Crystals polarize light, so using a polarizing filter to take pictures of crystals allows us to find information about their structures.

21. The display on your calculator uses polarization:

22. Demo of 3-D glasses in front of LCD TV screen: http://www.youtube.com/watch?v=dUA6nyvy -LY&feature=related http://www.youtube.com/watch?v=dUA6nyvy -LY&feature=related

24. Making rainbows since 1997