Periscope

A periscope is a simple optical instrument that uses the principle of reflection of light to allow people to see objects that are not in their direct line of sight. It is especially useful for observing objects over or around obstacles. The device is made using two mirrors placed at specific angles to reflect light and guide the image from one point to another.

Structure of a Periscope:

1. Cardboard Tube or Box: Serves as the body of the periscope, enclosing the mirrors and guiding the light.
2. Two Mirrors: Fixed at 45° angles, they reflect light from the object to the viewer.
3. Windows: Openings at the top and bottom allow light to enter and exit the periscope.

Periscope

Working:

• Light from the object enters the top opening of the periscope.
• The light hits the first mirror, which is placed at a 45° angle, and is reflected downwards.
• The light then hits the second mirror, also at a 45° angle, and is reflected sideways toward the viewer’s eye.
• This arrangement allows you to see the object without directly facing it.

Uses:

1. In submarines, it is used to observe objects above the water surface while remaining submerged.
2. In bunkers, it allows soldiers to monitor surroundings from a protected underground position.
3. In observation towers, it is used for keeping watch over large areas.

Periscope on a Submarine

1. Aim: To construct a periscope and observe how it uses the reflection of light to see objects not directly visible.

2. Materials Required: cardboard box, two small mirrors, sticking tape, and scissors or cutter.

3. Procedure

• Take a cardboard box and make slits on the top and bottom sides.
• Place two mirrors inside the box at an angle of 45°, parallel to each other, and secure them with sticking tape.
• Cut two small windows (about 1 inch each) near the mirrors- one at the top and one at the bottom.
• Look through the bottom window and observe what is visible through the top window.

Periscope

4. Observation: When you look through the bottom window, you can see objects in front of the top window, even if they are not directly in your line of sight.

5. Conclusion: The periscope works on the principle of reflection of light, where light reflects off two mirrors placed at 45° angles, allowing the user to see objects that are out of their direct view.