Happy Friday!!! 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
Warm up # 2 Light travels through a liquid at 2.25 x 10 8 m/s. What is it’s index of refraction?
Notes- light and polarization Light is a transverse wave NOT a compression wave
Light travels from all directions
Light can be “polarized” Polarized light waves are light waves in which the vibrations occur in a single plane.
“Polarization” occurs when a transverse wave is able to pass through a material only if it is oscillating in a certain direction.
Light polarization Unpolarized polarized
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.
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.
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.
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!
polarized light polarization 2
Old-style 3D movies used Red & Blue filters:
A polarizing filter is often used in photography to reduce glare from smooth surfaces:
This picture was taken with a polarizing filter. It allows us to see “strain” on the eyeglasses.
Crystals polarize light, so using a polarizing filter to take pictures of crystals allows us to find information about their structures.
The display on your calculator uses polarization:
Demo of 3-D glasses in front of LCD TV screen: -LY&feature=related -LY&feature=related
Making rainbows since 1997