Periscope Inventors Sir Howard Grubb and Simon Lake

Periscope Inventors Sir Howard Grubb and Simon Lake A periscope  is an optical device for conducting observations from a concealed or protected position. Simple periscopes consist of reflecting mirrors and/or prisms at opposite ends of a tube container. The reflecting surfaces are parallel to each other and at a 45 ° angle to the axis of the tube. The Military This basic 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. Tanks  use periscopes extensively: They allow military personnel to check out their situation without leaving the safety of the tank. An important development, the  Gundlach rotary periscope, incorporated a rotating top, allowing a tank commander to obtain a 360-degree field of view without moving his seat.  This design, patented by  Rudolf Gundlach  in 1936, first saw use in the  Polish  7-TP  light tank (produced from 1935 to 1939).   Periscopes also  enabled soldiers to see over the tops of trenches, thus avoiding exposure to enemy fire (especially from snipers).  During  World War II, artillery observers and officers used specifically-manufactured periscope binoculars with different mountings. More complex periscopes, using  prisms  and/or advanced fiber optics instead of mirrors, and providing magnification, operate on  submarines  and in various fields of science. 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.​ Sir Howard Grubb   The Navy attributes the invention of the periscope (1902) to Simon Lake and the perfection of the periscope to Sir Howard Grubb. For all its innovations,  USS Holland  had at least one major flaw; lack of vision when submerged. The submarine had to broach the surface so the crew could look out through windows in the conning tower. Broaching deprived the Holland of one of the submarine’s greatest advantages – stealth. Lack of vision, when submerged, was eventually corrected when Simon Lake used prisms and lenses to develop the omniscope, forerunner of the periscope. Sir Howard Grubb, a designer of astronomical instruments, developed the modern periscope that was first used in Holland-designed British Royal Navy submarines. For more than 50 years, the periscope was the submarine’s only visual aid until underwater television was installed aboard the nuclear-powered submarine  USS Nautilus. Thomas Grubb (1800-1878) founded a telescope-making firm in Dublin. Sir Howard Grubbs father was noted for inventing and constructing machinery for printing. In the early 1830s, he made an observatory for his own use equipped with a 9-inch (23cm) telescope. Thomas Grubbs youngest son Howard (1844-1931) joined the firm in 1865, under his hand the company gained a reputation for the first-class Grubb telescopes. During the First World War, demand was on Grubbs factory to make gunsights and periscopes for the war effort and it was during those years that Grubb perfected the periscopes design.

A Guide to Plankton

A Guide to Plankton Plankton is a general term for the floaters, the organisms in the ocean that drift with the currents. This includes zooplankton (animal plankton), phytoplankton (plankton that is capable of photosynthesis), and bacterioplankton (bacteria). Origin of the Word Plankton The word plankton comes from the Greek word planktos, which means wanderer or drifter. Plankton is the plural form. The singular form is plankter. Can Plankton Move? Plankton are at the mercy of the wind and the waves, but not all are completely immobile. Some types of plankton can swim, but only weakly or vertically in the water column. And not all plankton are tiny - jellyfish (sea jellies) are considered plankton. Types of Plankton Some marine life goes through a planktonic stage (called meroplankton) before they become frees of animals that have a meroplankton stage are corals, sea stars (starfish), mussels and lobster. Holoplankton are organisms that are plankton their entire lives. Examples include diatoms, dinoflagellates, salps, and krill. Plankton Size Groups Although most people think of plankton as microscopic animals, there are larger plankton. With their limited swimming capability, jellyfish are often referred to as the largest type of plankton. In addition to being categorized by life stages, plankton can be categorized into different groups based on size. These groups include: Femtoplankton - Organisms under 0.2 micrometers in size, e.g., virusesPicoplankton - Organisms 0.2 micrometer to 2 micrometers, e.g., bacteriaNanoplankton - Organisms 2-20 micrometers, e.g. phytoplankton and small zooplanktonMicroplankton - Organisms 20-200 micrometers, e.g., phytoplankton and small zooplanktonMesoplankton - Organisms 200 micrometers to 2 centimeters, e.g., phytoplankton and zooplankton such as copepods. At this size, the plankton are visible to the naked eye.Macroplankton - Organisms 2 centimeters to 20 centimeters, e.g., like ctenophores, salps, and amphipods.Megaplankton - Organisms over 20 centimeters, like jellyfish, ctenophores, and amphipods. The categories for the smallest plankton sizes were needed more recently than some others. It wasnt until the late 1970s that scientists had the equipment available to help them see the great number of planktonic bacteria and viruses in the ocean. Plankton and the Food Chain A plankton species place in the food chain depends on what type of plankton it is. Phytoplankton are autotrophs, so they make their own food and are producers. They are eaten by zooplankton, which are consumers.   Where Do Plankton Live? Plankton live in both freshwater and marine environments. Those that live in the ocean are found in both coastal and pelagic zones, and in a range of water temperatures, from tropical to polar waters. Plankton, As Used in a Sentence The copepod is a type of zooplankton and is a primary food for right whales. References and Further Information: Australian Museum. What Is Plankton?  Accessed October 31, 2015.Bigelow Laboratory. Cycling Through the Food Web.  Accessed October 31, 2015.Microbial Grazers Lab. Marine Biological Laboratory at Woods Hole. Accessed October 31, 2015.