By simply limiting a light source to the size of a pinhole we can begin to understand how both the camera and the human eye work to record light. Experimentations done using camera obscura led to many great discoveries, not the least of which was the invention of photography. Building a camera obscura is as simple as cutting a hole in a box, and can be modified easily to make a pinhole camera that captures photos. Many photographers still use a pinhole lens to give their photos a dreamy look.
Greek mathematicians used camera obscura to determine that light travels in a straight line, helping us to understand the relationship between perspective and angles. More curriculum connectors can be found here.