Science Projects And Inventions

YOU  NEED:

• A large piece of card

Divide a large piece of card by creasing it in 4 parts lengthwise. Cut slots into its side at exactly 45 degrees an inch inside the edge of the card. Also cut square windows as shown in the diagram. Fold the card along the creases and fix the last edge with tape thus making a square tube. Take two small mirrors and slide them into the slots with the reflective sides facing each other so that both are visible through the two windows you had cut. The periscope is now ready for use.

HOW DOES IT WORK?

Light coming in from the upper slots reflects off from the upper mirror towards the lower mirror. Since the viewer is viewing the image at the position of the lower mirror, he image is visible to him on the lower mirror.