Why do we need 3D glasses for 3D movies

• In order to see things in 3D each eye must see a slightly different picture.The brain then puts the two pictures together to form one 3D image that has depth to it.

• Since your eyes are about two inches apart, they see the same picture from slightly different angles

• Your brain then correlates these two images in order to gauge distance. This is called binocular vision

• Your brain has the ability to correlate the images it sees in its two eyes even though they are slightly different

• The same scene is projected simultaneously from two different angles in two different colors, red and cyan (or blue or green). Here's where those cool glasses come in -- the colored filters separate the two different images so each image only enters one eye. Your brain puts the two pictures back together and now you're dodging a flying image