Camera Obscura Focal Inversion Box
An engaging, screen-free learning activity that builds real-world creativity and critical thinking for kids aged 7 to 9.
Materials Needed
- • Cardboard shoebox with lid (1 unit)
- • Small magnifying glass or optical convex lens (1 unit)
- • Translucent tracing paper (1 sheet)
- • Black cardstock or matte black paint (1 set)
- • Duct tape (1 roll)
Pro Tips
- → Paint the inside of the shoebox matte black to eliminate stray internal light reflections.
- → Point the lens end toward a brightly sunlit window or lamp while looking at the tracing paper screen in a dim room.
- → Notice that the projected image on the paper screen is flipped upside-down and reversed left-to-right, just like the human retina.
Safety First
Adult handles craft knife cuts in shoebox walls.
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Step-by-Step Instructions
Step 1
Paint the interior of a shoebox with black paint or line it with black cardstock to eliminate light bounce.
Step 2
Cut a round aperture in one short end of the box and secure a small convex magnifying glass lens over the hole with duct tape.
Step 3
Insert a vertical slide of translucent tracing paper across the interior of the box to serve as the focal projection screen.
Step 4
Cut a viewing peephole in the back, point the lens toward a brightly sunlit window, and view the upside-down projected moving landscape.