How to Make a Cardboard Periscope

Building with Milk Cartons

• 1

  Cut the triangular top off of a carton.

• 2

  Draw a 2-inch wide rectangular hole about 1/4-inch from the sides and bottom of the carton on one panel. This makes the front of the periscope.

• 3

  Measure the bottom of the carton, and mark that height on both sides along the back of the carton. Draw right-angle triangles from that mark to the bottom-front corners.

• 4

  Hold the mirrors along those lines so the center of the mirror lines up with the mid-point of the line. Trace the edge of the mirror on both sides to create an angled slot.

• 5

  Slide the mirrors into the slot, and tape them into place.

• 6

  Repeat steps 1 through 5 with the remaining carton and mirror.

• 7

  Pinch the corners of the open top on one of the cartons, then slide that carton into the top of the other one, so the view-hole on one carton is on the opposite side of the other.

• 8

  Tape around the join between the two cartons. To use the periscope, look through one view hole, and you will see the world through the other side.

Building with Card Stock

• 9

  Draw four 2- by 6-inch rectangles. Mark two of them as the "Front" and "Back."

• 10

  Extend one side of a remaining rectangle upward by 2 inches and the other side down by 2 inches. Connect those points with a 45-degree triangle, so you have a parallelogram. Repeat in reverse with one other rectangle.

• 11

  Cut out those shapes and assemble a tube using the parallelograms as the sides. Line up the corners of those shapes. Tape the tube together.

• 12

  Tape the mirrors to the lengths of the triangular ends of your periscope.