This experiment serves to acquaint students with basic information on the construction and use of the periscope. To their amazement, students discover that they can observe objects from a concealed position. They'll construct a simple periscope using mirrors to mimic the more complex periscopes that use prisms. Students follow the path of light as it travels from the first mirror to the second mirror and from the second mirror to the eye. They will use a protractor to measure the angles the light path makes as it bounces off of each mirror. During their research, they'll investigate the practical applications of the periscope beyond its use as a toy.
Construct and experiment with a periscope using reflected light rays to gather an image.
- black construction paper
- shoe box
- index cards
- aluminum foil
- Gather all the materials you will need for this project.
- Copy the observation sheet provided below so that you may make a sketch of your periscope, which includes a depiction of how the homemade mirrors are aligned. You will use this same sheet to record your observations.
- Start by making your own mirrors by using glue and placing aluminum foil on your index cards. Be careful! Make certain that the aluminum foil stays smooth and that you glue the shiny side up.
- Now take the shoe box and line it with black paper.
- Cut a hole in the bottom of the box about 3 cm from one end.
- Cut out a hole in the lid about 3cm from one end.
- Fold the ends of the aluminum foil mirrors, making tabs that you will now glue to the inside of the box. Using the wet tabs, fasten your mirrors at a 45 degree angle at both ends of the box. Use your protractor to measure and check the angle.
- While the glue is still wet, shine your flashlight into one of the openings. Look into the second opening and adjust the mirror so that you can clearly see the flashlight.
- Wait for the glue to dry. Now, put the lid back on the box and look through your periscope. Record what you see.What do you conclude?
- You may decide to change the positions of the mirrors and record your observations. Keep in mind that the light enters at the top and is reflected by the top mirror down to the bottom mirror. The light is then reflected from the bottom mirror to the person's eye.
- Try hiding objects and use your periscope to look around corners to find them.
- Write up your report. Be certain to include your research in a bibliography. You may wish to include photos of your homemade periscope as well as a diagram of how the light rays are reflected. Hint! The periscope is a great gift for a younger brother or sister!