Periscope

A periscope helps you see.

It lets you look around things. You can see over a wall. It can also work in a boat under the water.

Some use small mirrors. The mirrors sit at an angle. They bounce light to your eye. This lets you see things in front of you.

Other types use glass shapes. These shapes are called prisms. They also bend light to help you see.

Soldiers used them in long holes called trenches. This helped them stay safe. They could look up without being seen.

Tanks use them too. They let drivers see outside. This keeps the tank strong and safe. It is a very handy tool!

A periscope is a tool that helps you see. It lets you look over or around objects. This is useful when you cannot see directly.

Simple periscopes use mirrors. These mirrors sit at a 45° angle. They bounce light from an object to your eye. Other types use prisms. Prisms are glass shapes that bend light.

Soldiers used periscopes in trenches during World War I. This helped them see over the top safely. Tanks also use them. They let drivers see outside without making weak holes in the armor. Some tanks use a special part called an episcope. An episcope stays in one fixed place.

Submarines use periscopes to see above the water. They often use prisms instead of mirrors. Prisms are more rugged and stay strong. Some submarines have two periscopes. One is for looking around. The other is for targeting. Modern ships may use photonics masts instead. These use electronic sensors to send images to a screen.

A periscope is a clever tool for seeing. It helps people look over, around, or through things. This is useful when something blocks your view. For example, you might not be able to see directly in front of you.

A simple periscope uses an outer case with mirrors. These mirrors sit at a 45° angle to each other. They bounce light from an object down to your eye. Other versions use prisms, which are glass shapes that bend light.

Some complex versions even use fiber optics to show images.

How a periscope works depends on its design. A basic model uses two parallel mirrors to move light. More advanced ones use prisms or lenses to make things look clearer. Some periscopes even provide magnification. This means they make distant objects look much larger. A submarine periscope is often just two telescopes pointed at each other. If the two telescopes have different magnification levels, the image changes size. This allows a person to see things far away with great detail.

Many people helped improve the periscope over many years. In 1647, Johannes Hevelius described an early version. He called it a "polemoscope" and used lenses. Later, Mikhail Lomonosov made an "optical tube" that was very similar. In 1854, Hippolyte Marié-Davy invented a naval periscope using two small mirrors. By 1902, Simon Lake created a collapsible version for submarines. He called his invention the "omniscope." Sir Howard Grubb also worked to perfect the device during World War I.

Periscopes have been used in many important places. During World War I, soldiers used them in trenches. This let them see over the top without being in danger. Tanks also use them to protect the people inside. Instead of cutting holes in the armor, drivers use periscopes to look out. In 1936, Rudolf Gundlach patented a rotating periscope. This allowed tank commanders to see in a full 360-degree circle. His design was used in many tanks, including the Polish 7-TP and the American Sherman.

Today, periscopes are still very important in science and the navy. Submarines use them to search for things at the surface. Modern submarine periscopes often use prisms instead of mirrors. Prisms are more rugged and can handle the water better. Some submarines even have two different scopes. One is for looking around, and the other is for targeting. Some very new submarines now use photonics masts. These use electronic sensors to send images to a screen instead of using a long tube.

A periscope is a specialized optical device used for observation. It allows a person to see over, around, or through obstacles. This is essential when a direct line-of-sight is blocked.

In its most basic form, a periscope uses an outer case with two parallel mirrors. These mirrors are set at a 45° angle to reflect light. More advanced versions use prisms or fiber optics to provide better images. These complex systems can also provide magnification to see distant objects clearly.

The mechanism of a periscope relies on the path of light. In a simple mirror-based model, light hits the top mirror at a 45° angle. This causes the light to bounce downward through the tube. The light then hits the bottom mirror, which is also at 45°. This second reflection directs the light into the observer's eye.

More sophisticated designs use lenses or prisms to manipulate light. A lens periscope uses an objective lens to collect light. It may also use a field lens and an image-erecting lens. These components ensure the image appears upright and clear to the viewer.

Periscopes can be categorized by their design and specific function. Simple periscopes use mirrors, while naval or scientific models often use prisms. Prisms are glass shapes that use total internal reflection to move light. This method is much more rugged than using mirrors. Submarine periscopes are often described as two telescopes pointed at each other. If the telescopes have different magnification levels, the image will be magnified or reduced. Some specialized versions, like the Embedded Image Periscope, use digital sensors to project images onto a screen.

The history of the periscope spans several centuries of invention. In 1647, Johannes Hevelius described an early version called a "polemoscope" in his work *Selenographia*. Mikhail Lomonosov later invented an "optical tube" that functioned similarly. In 1854, Hippolyte Marié-Davy created the first naval periscope using two small mirrors. Simon Lake improved submarine technology in 1902 with a collapsible "omniscope." During World War I, Sir Howard Grubb worked to perfect the device for military use.

Military applications have driven much of the periscope's development. During World War I, soldiers used periscopes in trenches to avoid enemy fire. Some infantry rifles were even fitted with periscopes so shooters could aim from safety. In tanks, periscopes protect occupants by removing the need for vision slits in the armor. A related device called a protectoscope allows a vision slit to be covered by armored plate. In 1936, Rudolf Gundlach patented a rotating periscope. This allowed tank commanders to achieve a 360-degree field of view without moving their seats.

Submarines rely heavily on periscopes for survival and combat. A submarine can use a periscope to search for targets while remaining submerged. Because the periscope creates a visible wake, commanders must use them with great discretion. Traditionally, submarines carried two different types of scopes. An observation periscope provides a wide field of view for scanning the surface. A targeting periscope provides high magnification to help aim torpedoes. Modern submarines are now transitioning to photonics masts, which use electronic sensors instead of long physical tubes.

Periscopes have also found use in aviation and specialized vehicles. The *Spirit of St. Louis* was the first known aircraft to use a periscope. Other aircraft, such as the Vickers VC10 and the B-52, used them for various sighting or navigation needs. In the past, B-52 crews used sextant periscopes for celestial navigation. Even high-speed aircraft like the North American X-15 have utilized periscopes. These tools show how the science of light can be applied to many different environments.