Up, Periscope!

Have you ever seen a film about a submarine? Do you know how do the sailors in the sub look around above the water surface? They use a periscope - a long tube containing mirrors arranged so that, when you look into one end, you see the reflection of whatever the other end is pointing at!

It's really pretty easy to make your own periscope. There's some measuring and cutting involved, so you need to get some adults involved.

What you'll need:
Periscope body pattern (download PDF file here)
Cardboard (posterboard is OK)
Scissors
Ruler
Tape
2 small square mirrors that fit into your periscope (buy these after you make the periscope body)

Enlarge the periscope body pattern and transfer it to the cardboard. Make two holes where the white squares are located. Cut narrow slits where the heavy black lines are shown (slits must make a 45^o angle with the side of the periscope). Lightly score the cardboard along the red lines to make it easier to fold.

Fold the pattern to form a long rectangular tube and tape is closed. It should look more or less like the picture at right. Find two mirrors that will slide into one slit, across the tube, and out the slit on the other side. Insert the bottom mirror with the reflective side facing up. Insert the top mirror with the reflective side down. Use tape to hold the mirrors in place. If you look into either square hole, you should be able to see a reflection.

To use the periscope, look into the bottom hole while holding it straight up. You won't be able to see directly ahead, but will see things that are higher up than your eyes. When you hold the periscope upright, you can even see over walls or tall people's heads! When you hold it sideways, you can peek around corners! Take your periscope outside or use it around the house, and see what you can see!