Definition of periscope

The word "periscope" originated during World War II as a solution for the British Navy's urgent need to overcome the limitation of submarines' restricted horizontal visibility in deep water. The term "periscope" is derived from the Greek words "peri," meaning around, and "skopein," meaning to look or see. The conventional periscope in submarines used mirrors and lenses to lift the view out of the submarine, allowing a submarine commander to see above the surface without the need for the submarine to surface. Prior to the invention of periscopes, submarine commanders had to rely on other means to gain exterior views, such as creating perforations in the hull for observers or opening a hatch, both of which posed significant dangers as they could expose the submarine's location and put the submarine at risk of attack or detection. In 1934, the German Navy was the first to develop and use a submarine periscope during their exercises, and in the following years, various countries adopted and improved the device. The British Navy took it up during World War II and referred to it as a "snorkel periscope" as it could also supply the submarine's oxygen requirements. Today, periscopes continue to be a crucial component of modern submarine design, enabling submariners worldwide to navigate, observe, and defend underwater without exposing themselves to any potential danger from the surface.