What Is Periscope?

A periscope is defined as an instrument used for observing over, around or through an obstacle or object which is prevented by direct line of sight. It consists of an outer case with mirrors at each end at 45° angle. These mirrors are placed parallel to the surface. Jules Carpentier, a French engineer and inventor designed the submarine periscope. It was widely used during World War II in tanks and armoured vehicles.


Real Time Picture of Periscope

How To Use Periscope?

A periscope works on the basis of laws of reflection of light. Any object in the line of sight reflects the light making it visible in the periscope.

The mirrors are placed at an angle of 45° such that when light falls on one of the mirrors, it gets reflected back making it fall on the other mirror which further gets reflected back to the observer’s eyes. But in more complex periscopes, prisms are used in place of mirrors. The instrument does not produce any magnification and crossline images.

Periscope Science Project


The main objective of this experiment is to learn how to prepare a periscope and can be used in the peak or pool and around the corner.


  • 2 mirrors of circular in shape
  • 2 PVC pipes of 12″ sections, having a diameter slightly a bit larger than that of the other so that they can easily slide up & down when clubbed together
  • 2 elbow joints- PVC: one is to fit smaller pipe and the other to fit a larger one
  • Putty


  1. Make use of putty in order to stick back of mirrors to the inner surface of PVC pipes at an angle of 45°. Why do you think this angle is the best? What can happen if suppose this angle was a bit larger or even smaller?
  2. Attach these inner surfaces to pipe with the same size.
  3. Slide larger pipe coming over the smaller one
  4. Decorate it! Yes, paint the patterns helping you in staying hidden.
  5. Look out the elbow eye-piece placed on the smaller portion of the pipe and then explore it! You can even slide onto the larger side of the pipe in an up & down position in order to extend the length of the periscope.


Then there is your Periscope.

Uses Of Periscope

Other than viewing objects that are not in the direct line of sight, the following are various other uses of periscope:

  • It is used in submarines to determine the distance of a torpedo and helps in deciding the right time for the attack.
  • It is used in a nuclear reactor to observe the chemical reactions that are taking place.
  • In military periscopes are used to observe from their hiding position. The main disadvantage of a periscope is that it can be used by one person at a time.
  • Tanks and armoured vehicles use the periscope to inspect the surrounding.

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Test your Knowledge on Periscope


  1. this website is very nice and also helpful . It helped me to complete my projects and also provided information which otherwise would not be easy to find on other websites .
    Keep it up !!!

  2. this article was very helpful for me …thanks for the favour..

  3. Good explanation and a very good website

    1. Good explanation and very good article and very good website

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