Why people use periscopes

A periscope is a useful example of the law of reflection at work. This sends light directly down the tube and onto the lower mirror. Describe how light rays can change direction. 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.

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. Principle of the periscope. The periscope on the left uses mirrors whereas the right uses prisms.

Principle of the lens periscope. The two periscopes differ in the way they erect the image. The left one uses an erecting prism whereas the right uses an erecting lens and a second image plane.

A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position.

In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a degree angle. This form of periscope, with the addition of two simple lenses, served for observation purposes in the trenches during World War I. Military personnel also use periscopes in some gun turrets and in armoured vehicles.

The overall design of the classical submarine periscope is very simple: two telescopes pointed into each other. If the two telescopes have different individual magnification, the difference between them causes an overall magnification or reduction. Australian Light Horse troops using a periscope rifle , Gallipoli , Photograph by Ernest Brooks. A team of German artillery observers using periscope binoculars, Johannes Gutenberg , known for his contribution to printing technology, marketed a kind of periscope in the s to enable pilgrims to see over the heads of the crowd at the vigintennial religious festival [ which?

Johannes Hevelius described an early periscope with lenses in in his work Selenographia, sive Lunae descriptio [Selenography, or an account of the Moon]. Hevelius saw military applications for his invention.

A periscope works on the reflection of light from two plane mirrors arranged parallel to one another. Like in tanks, submarines or evenalone. Periscope: Periscope is an example wherein mirrors are placed at 45 degrees w. The light from the object is incident on the mirror M1 at an angle of 45 degrees. A periscope is an optical instrument that uses a system of prisms, lenses or mirrors to reflect images through a tube. Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube.

This activity is part of the Optics Educator Guide. Light is always reflected away from a mirror at the same angle that it hits the mirror. Hence, the image formed in a periscope is reflected, and therefore is not real. Answer: This is because the light rays from the object are reflected by two mirrors. Periscopes on submarines may be as long as 60 feet 18 m. When a submarine is submerged to a depth that is equal to the length of the periscope tube, it is considered to be at periscope depth.

Note: For a simple periscope, only plane mirrors are used. For some distance visions, an enlarged view of the object is required and hence convex mirrors are helpful.

The military typically uses periscopes in armored vehicles and gun turrets. The word periscope derives from two Greek words. Besides reflecting prisms, periscopes on submarines usually have two telescopes. A submarine features heavy-duty, thick waterproof casing that makes it sturdy enough to withstand high water pressure. Johann Gutenberg offered a periscope to allow pilgrims to see objects over the heads of others at a religious festival in the s.

When you have programmed both telescopes to have two different sizes of magnification at the same time, the magnification difference between the telescopes results in either an overall enlargement or reduction of the images. The main purpose of the development of the periscope in a submarine was to provide a way to see above the surface while still underwater. Most navies around the world use similar instruments, but employ various designs.