Why does a periscope work

When you are making a periscope, it's important to make sure that your mirror is positioned at a degree angle. If you use a wider milk carton or some other box, just measure how wide your box is. Then measure that same distance up the side of the box and make a mark. The line between your mark and the opposite corner of the box will be at 45 degrees.

How does my periscope work? Light always reflects away from a mirror at the same angle that it hits the mirror. In your periscope, light hits the top mirror at a degree angle and reflects away at the same angle, which bounces it down to the bottom mirror. That reflected light hits the second mirror at a degree angle and reflects away at the same angle, right into your eye.

You can make your peri- scope longer, but the longer the tube is, the smaller the image you'll see. Periscopes in tanks and submarines have magnifying lenses between the mirrors to make the reflected image bigger. This and dozens of other cool activities are included in the Exploratorium's Science Explorer books, available for purchase from our online store. Two 1-quart milk cartons Two small pocket mirrors flat, square ones work best Utility knife or X-Acto knife Ruler Pencil or pen Masking tape.

An X-Acto knife is very, very sharp. Have a grown-up do all the cutting in this activity. Cut a hole at the bottom of the front of one milk carton. How does the periscope work? Can you trace the path of light from the object, through the periscope, to your eye?

How could you build your periscope to see behind you? When would you use a periscope? Optional: If your students are younger and need help with careful cutting, measure and cut the slit for the mirror. See step 4 in the instructions below. Repeat with the second carton. Hint: You can create a forward-looking periscope by facing the mirrors in opposite directions, or a backwards-looking one by facing the mirrors in the same direction.

Details Activity Length 30 mins. In this activity, students use the law of reflection to create their own periscope.

Objectives Describe how light rays can change direction. Demonstrate how visible light is reflected. Materials Per Adult: 1 craft knife Per Student: 2 clean 1-litre milk or juice cartons 2 small, flat mirrors less than 9 cm in at least one dimension ruler marker tape scissors Key Questions How does the periscope work?

What To Do Preparation Use a craft knife to cut off the top of each carton. Using a marker, draw a square at the bottom of each carton. If you put your finger under one end and look into the other end, your finger will look as long as the periscope! Website by Mrs deBoeck , last updated May You can email comments or questions to scienceclub webinnate.

Click on the picture to enlarge. Glue the template securely to the cardboard. If you can print it straight onto the card, even better. Cut template out carefully along the solid lines. Don't cut the tabs off! This is the shape you should be left with. Get an adult to score along every dotted line. Fold carefully you can fold round the ruler along all the scored dotted lines.

Use tape or strong glue to stick the periscope together using the tabs. Stick one mirror into each end, facing each other.