The camera obscura (Latin for "dark chamber") demonstrates an odd optic phenomenon. When light from a bright scene enters a darkened space through a tiny hole, the resulting image appears upside down. See for yourself with this homemade viewer that turns everything you look at topsy-turvy.
This project was adapted from the Pringles pinhole camera on exploratorium.edu. To learn more about how the camera works, visit the website and search for "Pringles pinhole."
Measure and draw a line around the can 2 inches from the bottom. Cut through the line with the craft knife (a parent's job) to create two can sections. Trace the bottom of the can onto a sheet of vellum, then cut the circle out.
Stack the pieces in this order: the bottom of the can (open end up), the lid, the vellum circle, and the top of the can.
Thoroughly wrap the seam with duct tape so that no light can come in.
Flip the viewer over and use the pushpin to make a small hole in the center of the can's bottom.
For a more finished look, cover the viewer with paper secured with double-sided tape. To use your viewer, hold it up to one eye and gaze at a bright scene (something lit by sunlight works best). To block out light, use one hand to cup the viewer to your eye.