Cardboard Tube Pinhole Projector

Smithsonian Institution Libraries

These exercises and lesson plans are designed to accompany and enrich the study and discussion of the June 2004 Transit of Venus.





Students build pinhole projectors that can be used to safely watch the Transit using cardboard tubes

Grade Level:



  • Observe the properties of light safely
  • Construct an instrument that allows the observation of solar events

Subject Area or Standard:


Materials Needed:

  • Long box (at least 6 feet long-the longer the box, the bigger the image)
  • Aluminum foil
  • Pin
  • Sheet of white paper




NEVER view the sun with the naked eye or with any optical device such as binoculars or a telescope

anatomy of eyeThe lens in your eye will focus the sun's rays onto the back of your retina resulting in permanent damage or blindness.



1. Find or make a long box or tube.
2. Cut a hole into one end of the box and cover with aluminum foil
3. Poke a hole in the center of the aluminum foil with a pin
4. Cut a viewing hole in the side of the box near one end.
5. Place the white sheet of paper into the end of the box near the viewing hole.
6. Position the end of the box with the aluminum foil and pinhole toward the sun.
7. Find the round spot of light on the white sheet of paper. That is the image of the sun.


1. Use two cardboard tubes from paper towel rolls.
2. Place aluminum foil over one end of one tube and hold with rubber band
3. Place a single sheet of tissue sheet over other end of cardboard tube
4. Attach the second cardboard tube over the tissue-encased end and tape the two tubes together.
5. Punch a pinhole into the center of the aluminum foil
6. In a darkened room point aluminum end of tube toward daylight
7. Observe image on tissue paper.
diagram of alternative viewing device