Periscope

A periscope is an optical instrument for viewing objects that are not directly in the observer's line of sight. Periscopes in submarines enable crew members to see above the water without bringing the submarine to the surface. The periscope on an army tank enables the men inside to view the area surrounding the tank while remaining protected. Scientists use periscopes to view dangerous experiments, such as nuclear reactions, from a safe position.

The simplest type of periscope consists of two reflecting pieces, either mirrors or prisms, set into a tubelike apparatus. The reflecting surfaces may be parallel or at right angles, depending on whether the observer is looking forward or to the rear. Light rays entering the tube are reflected through the body of the tube to the eye of the observer.

The submarine periscope is more complicated in design. The length of the tube may be as much as 50 times its diameter. The image is transmitted through the tube by a system of prisms and lenses that provide a wide field of view.

More by this Author

  • Bushido
    0

    Bushido, or Way of the Samurai, a code of conduct in Japan not unlike the chivalric codes of European knights. It stressed complete loyalty to one's master, bravery, and a hard spartan life-style. Unlike European...

  • How Do Charities Work?
    0

    The term 'charity' popularly connotes the relief of poverty. In English law it has a wider meaning and comprises four principal divisions into which charitable objects have been classified, namely those: (1) for the...

  • The White House
    0

    The White House as it appears from the north. Photograph by David Lat. The White House is the official residence of the President of the United States, located in Washington, D.C. It is on Pennsylvania Avenue facing...


Comments

No comments yet.

    Sign in or sign up and post using a HubPages Network account.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.


    Click to Rate This Article
    working