How Does a Periscope Work?

A periscope is built like and works much like a telescope, with a long tube containing a mirror at each end. The mirrors are fitted into the tube so that they are parallel to each other at a 45° angle to the axis, or imaginary long center line, of the tube.

More complicated periscopes have extra lenses added to enlarge the image. Submarine periscopes contain this more complicated arrangement. They have reflecting prisms at the top and bottom of the tube, with two telescopes and several lenses between the two ends, and an eyepiece at the viewing end. A submarine periscope also has a thick, rigid, waterproof casing and can stand the pressure of great depths of water.

In addition to submarines, tanks also use periscopes in wartime to navigate or look for enemy targets. Both of these vehicles have periscopes which can be raised or lowered, as well as turned around in a 360° circle.

Periscopes can also be built so they see around corners!


  1. Anonymous says

    But let’s say you are 500 feet beneath the water, you can’t just extend 500 feet of tubings to the surface.

  2. Anonymous says

    Periscopes are also known to use Triangular prisms instead of flat mirrors, however the same principles still apply. The hypotenus of the prisms must be parallel from each other, and at 45 degrees from the axis.

  3. Anonymous says

    Submarines don’t have windows either so they use the periscopes to look ahead of them, not only above the water… I think xD

  4. Poopy Doo says

    who the heck is Amber u Creep just stay away from me im telling my mummy and my pet periscope, he’s a very good listener

  5. Jodie-Ann says

    What do i need to make a periscope ?, i am making one in science and i have to take in materials for it.

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