Periscope

A periscope, in its simplest form, is a device with two parallel mirrors, at 45 degree angles with respect to the line between them, that allows viewing in a given direction as if one is at a different position, in particular viewing in a horizontal direction as if one is in a higher position. It is used as a toy, and for seeing over people's heads in a crowd. More complex periscopes, using prismss instead of mirrors, and providing magnification, are used on submarines.

Table of contents

1 Early examples 2 Naval use 3 A cost-effective way of making a sturdy demonstration periscope 3.1 Equipment Required (to Make Demo Periscope) 3.2 Method for making the demonstration periscope

Early examples

Johann Gutenberg, better known for his contribution to printing technology, marketed a periscope in the 1430s to enable pilgrims to see over the heads of the crowd at the vigintennial religious festival at Aix-la-Chapelle.

Periscopes, in some cases fixed to rifles, were used in World War I to enable soldiers to see out of the trenches.

Naval use

A simple, fixed naval periscope using plane mirrors was built by the Frenchman Marie Davey in 1854. Thomas H. Doughty of the US Navy later invented a prismatic version for use in the American Civil War (circa 1891).

The invention of the collapsible periscope for use in submarine warfare is usually credited to Simon Lake in 1902, who called his device the omniscope or skalomniscope. There is also a report that an Italian, Triulzi, demonstrated such a device in 1901 calling it a cleptoscope.

A modern submarine periscope incorporates lenses for magnification and functions as a telescope. It typically employs prismss and total internal reflection instead of mirrors. It may have additional optical capabilities such as range finding and targeting. The mechanical systems of submarine periscopes are typically hydraulically powered and need to be quite sturdy to withstand the drag through water. The periscope chassis may also be used as to support a radio or radar antenna.

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A cost-effective way of making a sturdy demonstration periscope

Equipment Required (to Make Demo Periscope)

• 2 pieces of plywood 45 cm × 10 cm and 0.9 cm thick
• 2 pieces of plywood at least 37 cm × 10 cm and 0.9 cm thick
• 2 pieces of plywood at least 11.6 cm × 10 cm and 0.9 cm thick
• 2 pieces of wood which are prism shaped at least 10 cm × 8.5 cm × 8.5 cm the internal angles shoul be 90° and 45°
• 2 plastic or glass mirrors 10 cm × 10 cm
• small screws to fit.
• Screwdriver
• Drill with suitable drill bits for the screws
• PVA Glue

Method for making the demonstration periscope

1. Cut the wood to the correct size and sand if need be.
2. Screw the 4 long pieces together as in fig 1.
3. Screw the prism shaped pieces of wood on either end as in fig 1. and attach mirrors with glue.
4. Attach ends as in fig 1.
5. It should look something like fig 2.