While designing an optics lab for a conceptual physics course, I came across a “box theater” activity.1 The box theater is a pinhole camera obscura made from a box that students put over their heads and shoulders. I use the activity as a capstone experience to explain optical systems. (Classroom demonstrations of the camera obscura have been described by others.2) First, the students build and experiment with a camera obscura made from a plastic cup and a convex lens with a focal length of 7.5 cm, and then “wear” the box theater. The difficulty with the box theater is the dimness of the image. A cloth drape has to be hung from the bottom of the box around the shoulders of the students to prevent light leakage, and the students have to wait a few minutes for their eyes to adjust to the darkness.

1.
Don
Rathjen
and
Paul
Doherty
, “
Personal Pinhole Theater
,” in
Square Wheels: An Exploratorium Science Snackbook
(
2002
).
2.
Matthew W.
Prull
and
William P.
Banks
, “
Seeing the light: A classroom-sized pinhole camera demonstration for teaching vision
,”
Teach. Psychol.
32
(
2
),
103
106
(
2005
).
3.
The “large” boxes are typically 18 in × 18 in × 24 in. These can be bought at U-Haul outlets and similar stores.
4.
Available from Surplus Shed, hwww.surplusshed.com, 50 mm × 500 mm double convex lens, item L1917D.
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