Pinhole Camera Activity

Activity 1

The Pinhole Scope

Introduction

Cameras have become a standard item in many households. Film is cheap and easy to make, but the cameras and they lenses they use have become expensive and complicated pieces of machinery. The principles behind cameras are still quite simple, however. The most basic type of camera is the pinhole camera, which can be made from a cigar box, aluminum foil, and sheet film. In this activity, we'll learn how to make a simple pinhole scope.

Procedure

Gather these items from your home or workplace:
- Cardboard tube from a roll of paper towels
- Cardboard tube from a roll of aluminum foil or plastic wrap (smaller diameter than the tube from the paper towels)
- a 2"x 2" piece of aluminum foil
- Scotch^TM magic tape (the type that is semi- transparent, not the clear, glossy kind)
- a rubber band
- a small pin, needle, or thumbtack
Make sure one of the cardboard tubes has a smaller diameter than the other
On one end of the smaller tube place several strips of the magic tape across the hole so that the hole is completely covered by the tape with some overlap between the strips
On one end of the larger tube place the aluminum foil over the hole so that it completely covers the hole and use the rubber band around the tube to hold the foil in place
With your pin or needle, poke a small hole in the center of the aluminum foil covering the hole
Slide the two tubes together so that the magic tape and the aluminum foil are on the same side. If you slide the little tube inside the bigger one, the magic tape should slide right up against the foil.
Find a bare light bulb or a bright light source (fluorescent lights don't work that well) that you can view with your new Pinhole Scope
Stand about 5-10 feet from the light and look at the light source through your Viewer. Slide the tubes back and forth until you see an image of the light in focus before your eyes.
To see multiple images of the light, poke several holes into the aluminum foil and point the Viewer at the light source.
Rotate your Scope while looking at the light. What do you notice about the images? Do they rotate with the scope?

How does a simple hole and a viewing screen (the magic tape) allow you to see an image of the light source? Why are the images upside-down? Can you draw the paths of light as they come from the light, through the hole, and onto the screen?

To read about Pinhole Cameras and the Path of Light, go to The Readings .