Camera obscura is latin for dark chamber. Every camera is basically a dark chamber with a hole to let light in and create an image but a camera obscura is usually just a box with a pinhole and the outside image is projected inside the box flipped upside down. This was first discovered by a philosopher in a dark room who found that a small hole in the wall was projecting an image of the bright day outside on the opposite wall. 
We used a camera that had been made out of a shoe box and a lens from a magnifying glass that had a screen inside on which the image from the lens was projected. The screen could be viewed through a viewfinder at the other end. The lens could be moved to focus the image. This was a more advanced camera than the pinhole camera that we built from an empty pringle can and I could get pictures of the trees and windows on a building outside using my phone looking though the viewfinder. 
The pringle can camera was a cylindrical box with a pinhole in the metal bottom of the can and a screen 6cm from the viewfinder where the image was projected. When pointed at a bright light bulb, an inverted image of the bulb was visible but the was not much detail. This is an image I took using my camera and you can see the shape of the bulb.
This is what the pringle camera looked like with electrical tape to hold together the part that was cut to put the screen in that would display the image and at the top to make a small square viewfinder to look through and block out light. 
