Special thanks to Bill Peebles, owner of the Lumina, Rialto, Colony and Studio theaters, for the projector and theater photos and his valuable assistance; Crawford Harris, owner of Reel Automation, for his assistance and advice; and the North Carolina School of Science and Mathematics for the optical toy photos in the Wileman Collection.

Movies are part of every modern culture. And while movies on VHS and DVD are extremely popular, nothing replaces the larger-than-life spectacle of a grandiose film, such as "The Patriot," filling the big screen. In the United States alone, there are more than 37,000 movie screens, a clear testament to just how much we love to go to the movies!

In this edition of HowStuffWorks, you will learn about the amazing projection system that makes watching a movie at a theater possible. Other articles in this series examine the theater screen and seating, the sound system and digital sound, THX and film distribution.

A projector is the key piece of technology in showing movies in theaters around the world.
To show a modern film-based movie, there are five things you absolutely need:

  • A way to advance each frame of the film
  • A way to project the image from the film
  • A way to read the audio
  • A surface to project the image on
  • A system to play the audio
A projector provides the first three items on our list. While movies are usually projected onto a screen, a large white wall is all you really need.