1. Shadows, Eclipses and 3D Movies

2. Shadows Umbra Penumbra Area of full shadow
Cone shaped with base at object
Penumbra
Area of partial shadow
Cone shaped w/ tip at object

3. Eclipses Occurs when one object moves into shadow of another
Penumbra causes partial eclipse
Umbra causes total eclipse
Solar eclipse
Moon between earth and sun
Occurs during new moon
Lunar eclipse
Earth between sun and moon
Occurs during full moon
Color due to light passing thru earth’s atmosphere
Why no eclipse each month?

4. Polarization
Polarized light is light whose waves vibrate in only one direction
Polarizing film selects components of light in films direction
One polarizer 50%
Crossed polarizers 0%
E.G. light bouncing off horizontal surface (glare)

5. Uses of Polarization Sun Glasses 3D Movies
Filters are vertical to block horizontal rays of glare
Also decrease brightness by 50%
3D Movies
Each eye must see its own view
Opposite polarizers placed in front of two projectors matches corresponding glasses
Switching polaroids produces inside out view