Stereoscope in the context of "Stereogram"

A pond is a small, still, land-based body of water formed by pooling inside a depression, either naturally or artificially. A pond is smaller than a lake and there are no official criteria distinguishing the two, although defining a pond to be less than 5 hectares (12 acres) in area, less than 5 metres (16 ft) in depth and with less than 30% of its area covered by emergent vegetation helps in distinguishing the ecology of ponds from those of lakes and wetlands.

Ponds can be created by a wide variety of natural processes (e.g. on floodplains as cutoff river channels, by glacial processes, by peatland formation, in coastal dune systems, by beavers). They can simply be isolated depressions (such as a kettle hole, vernal pool, prairie pothole, or simply natural undulations in undrained land) filled by runoff, groundwater, or precipitation, or all three of these. They can be further divided into four zones: vegetation zone, open water, bottom mud and surface film.

Sir Charles Wheatstone (/ˈwiːtstən/; 6 February 1802 – 19 October 1875) was an English physicist and inventor best known for his contributions to the development of the Wheatstone bridge, originally invented by Samuel Hunter Christie, which is used to measure an unknown electrical resistance, and as a major figure in the development of telegraphy. His other contributions include the English concertina, the stereoscope (a device for displaying three-dimensional images) and the Playfair cipher (an encryption technique).

The history of film technology traces the development of techniques for the recording, construction and presentation of motion pictures. When the film medium came about in the 19th century, there already was a centuries old tradition of screening moving images through shadow play and the magic lantern that were very popular with audiences in many parts of the world. Especially the magic lantern influenced much of the projection technology, exhibition practices and cultural implementation of film. Between 1825 and 1840, the relevant technologies of stroboscopic animation, photography and stereoscopy were introduced. For much of the rest of the century, many engineers and inventors tried to combine all these new technologies and the much older technique of projection to create a complete illusion or a complete documentation of reality. Colour photography was usually included in these ambitions and the introduction of the phonograph in 1877 seemed to promise the addition of synchronized sound recordings. Between 1887 and 1894, the first successful short cinematographic presentations were established. The biggest popular breakthrough of the technology came in 1895 with the first projected movies that lasted longer than 10 seconds. During the first years after this breakthrough, most motion pictures lasted about 50 seconds, lacked synchronized sound and natural colour, and were mainly exhibited as novelty attractions. In the first decades of the 20th century, movies grew much longer and the medium quickly developed into one of the most important tools of communication and entertainment. The breakthrough of synchronized sound occurred at the end of the 1920s and that of full color motion picture film in the 1930s (although black and white films remained very common for several decades). By the start of the 21st century, physical film stock was being replaced with digital film technologies at both ends of the production chain by digital image sensors and projectors.

3D film technologies have been around from the beginning, but only became a standard option in most movie theatres during the first decades of the 21st century.