Wikisnaps! We find what's interesting on Wikipedia, so you don't have to!

A 3-D (three-dimensional) film or S3D (stereoscopic 3D) film is a motion picture that enhances the illusion of depth perception. Derived from stereoscopic photography, a regular motion picture camera system is used to record the images as seen from two perspectives (or computer-generated imagery generates the two perspectives in post-production), and special projection hardware and/or eyewear are used to provide the illusion of depth when viewing the film. 3-D films are not limited to feature film theatrical releases; television broadcasts and direct-to-video films have also incorporated similar methods, primarily for marketing purposes. 3-D films have existed in some form since the 1950s, but had been largely relegated to a niche in the motion picture industry because of the costly hardware and processes required to produce and display a 3-D film, and the lack of a standardized format for all segments of the entertainment business. Nonetheless, 3-D films were prominently featured in the 1950s in American cinema, and later experienced a worldwide resurgence in the 1980s and '90s driven by IMAX high-end theaters and Disney themed-venues. 3-D films became more and more successful throughout the 2000s, culminating in the unprecedented success of 3-D presentations of Avatar in December 2009 and January 2010. Stereoscopic motion pictures can be produced through a variety of different methods. Over the years the popularity of systems being widely employed in movie theaters has waxed and waned. Though anaglyph was sometimes used prior to 1948, during the early "Golden Era" of 3-D cinematography of the 1950s the polarization system was used for every single feature length movie in the United states, and all but one short film. In the 21st century, polarization 3-D systems have continued to dominate the scene, though during the 60s and 70s some classic films which were converted to anaglyph for theaters not equipped for polarization, and were even shown in 3-D on TV. In the years following the mid 80s, some movies were made with short segments in anaglyph 3D. The following are some of the technical details and methodologies employed in some of the more notable 3-D movie systems that have been developed. In the case of RealD a circularly polarizing liquid crystal filter which can switch polarity 144 times per second is placed in front of the projector lens. Only one projector is needed, as the left and right eye images are displayed alternately. Sony features a new system called RealD XLS, which shows both circular polarized images simultaneously: a single 4K projector (40962160 resolution) displays both 2K images (2048858 resolution) on top of each other at the same time, a special lens attachment polarizes and projects the images. [READ THE REST OF THIS ARTICLE]

Rafting or white water rafting is a challenging recreational outdoor activity using an inflatable raft to navigate a river or other bodies of water. This is usually done on white water or different degrees of rough water, in order to thrill and excite the raft passengers. The development of this activity as a leisure sport has become popular since the mid-1970s. The modern raft is an inflatable boat, consisting of very durable, multi-layered rubberized or vinyl fabrics with several independent air chambers. The length varies between 3.5 m (11 ft) and 6 m (20 ft), the width between 1.8 m (6 ft) and 2.5 m (8 ft). The exception to this size rule is usually the packraft, which is designed as a portable single-person raft and may be as small as 1.5 metres (4.9 ft) long and weigh as little as 4 pounds (1.8 kg). Rafts come in a few different forms. In Europe, the most common is the symmetrical raft steered with a paddle at the stern. Other types are the asymmetrical, rudder-controlled raft and the symmetrical raft with central helm (oars). Rafts are usually propelled with ordinary paddles and typically hold 4 to 12 persons. In Russia, rafts are often hand made and are often a catamaran style with two inflatable tubes attached to a frame. Pairs of paddlers navigate on these rafts. Catamaran style rafts have become popular in the western United States as well, but are typically rowed instead of paddled. Grade 1: Very small rough areas, might require slight maneuvering. (Skill Level: Very Basic). Grade 2: Some rough water, maybe some rocks, might require some maneuvering.(Skill Level: Basic Paddling Skill). Grade 3: Whitewater, small waves, maybe a small drop, but no considerable danger. May require significant maneuvering.(Skill Level: Experienced paddling skills). Grade 4: Whitewater, medium waves, maybe rocks, maybe a considerable drop, sharp maneuvers may be needed. (Skill Level: Whitewater Experience). Grade 5: Whitewater, large waves, large volume, possibility of large rocks and hazards, possibility of a large drop, requires precise maneuvering (Skill Level: Advanced Whitewater Experience). Grade 6: Class 6 rapids are considered to be so dangerous as to be effectively unnavigable on a reliably safe basis. Rafters can expect to encounter substantial whitewater, huge waves, huge rocks and hazards, and/or substantial drops that will impart severe impacts beyond the structural capacities and impact ratings of almost all rafting equipment. [READ THE REST OF THIS ARTICLE]

Memphis Belle was the nickname of a B-17F Flying Fortress during the Second World War that inspired the making of two motion pictures: a 1944 documentary film: Memphis Belle: A Story of a Flying Fortress and a 1990 Hollywood feature film: Memphis Belle. The plane was named for pilot Robert K. Morgan's sweetheart, Margaret Polk, a resident of Memphis, Tennessee. Morgan originally intended to call the plane Little One, after his pet name for her, but after Morgan and his copilot, Jim Verinis, saw the movie Lady for a Night, in which the leading character owns a riverboat named the Memphis Belle, he proposed that name to his crew. In May 1943 it became the first U.S. Army Air Forces heavy bomber to complete 25 combat missions. The plane and crew then returned to the United States to sell war bonds. The original airplane is undergoing extensive restoration at the National Museum of the United States Air Force in Dayton, OH. The Museum has placed restoration of Memphis Belle near the top of its priorities. In the magazine Friends Journal of the museum's foundation, Major General Charles D. Metcalf (USAF-Ret.), the director of the museum, stated that it might take 810 years to fully restore the aircraft. Memphis Belle during refurbishment in 2003.By the Spring of 2009, considerable preparatory work had been accomplished, but the fuselage and wings were still disassembled. After stripping the paint from the aft fuselage of the aircraft, hundreds of names and personal messages were found scratched in the aluminum skin. During the plane's war bond tour, people were allowed to leave their mark on this war-time hero. [READ THE REST OF THIS ARTICLE]

Harvestmen are arachnids belonging to the order Opiliones. As of 2006, over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000. The order Opiliones can be divided into four suborders: Cyphophthalmi, Eupnoi, Dyspnoi and Laniatores. Well-preserved fossils have been found in the 400-million year old Rhynie cherts of Scotland, which look surprisingly modern, indicating that the basic structure of the harvestmen has not changed much since then. Phylogenetic position is disputed: their closest relatives may be the mites or the Novogenuata. Although they belong to the class of arachnids, harvestmen are not spiders, which are of the order Araneae rather than the order Opiliones. In some places, harvestmen are known by the name "daddy longlegs" or "granddaddy longlegs", but this name is also used for two other unrelated arthropods: the crane fly and the cellar spider. These arachnids are known for their exceptionally long walking legs, compared to body size, although there are also short-legged species. The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen with ten segments and cephalothorax, or prosoma and opisthosoma) are broadly joined, so that they appear to be one oval structure; they also have no venom or silk glands. The feeding apparatus (stomotheca) differs from other arachnids in that ingestion is not restricted to liquid, but chunks of food can be taken in. The stomotheca is formed by extensions from the pedipalps and the first pair of legs. They have a single pair of eyes in the middle of their heads, oriented sideways. Many species are omnivorous, eating primarily small insects and all kinds of plant material and fungi; some are scavengers, feeding upon dead organisms, bird dung and other fecal material. This broad range is quite unusual in arachnids, which are usually pure predators. Most hunting harvestmen ambush their prey, although active hunting is also found. Because their eyes cannot form images, they use their second pair of legs as antennae to explore their environment. An urban legend claims that the harvestman is the most venomous animal in the world, but possesses fangs too short or a mouth too round and small to bite a human and therefore is not dangerous. This is untrue on several counts. None of the known species have venom glands; their chelicerae are not hollowed fangs but grasping claws that are typically very small and definitely not strong enough to break human skin. [READ THE REST OF THIS ARTICLE] is not affiliated with or endorsed by wikipedia. wikipedia and the wikipedia globe are registered trademarks of
article content reproduced in compliance with wikipedia's copyright policy and gnu free documentation license
view our privacy policy and terms of service here