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Há 3 horas · Newton's first law expresses the principle of inertia: the natural behavior of a body is to move in a straight line at constant speed. A body's motion preserves the status quo, but external forces can perturb this. The modern understanding of Newton's first law is that no inertial observer is privileged over any other.
Há 1 dia · Tesla's rebuilt birth house (parish hall) and the church where his father served in Smiljan, Croatia.The site was made into a museum about him.. Nikola Tesla was born into an ethnic Serb family in the village of Smiljan, within the Military Frontier, in the Austrian Empire (present-day Croatia), on 10 July [O.S. 28 June] 1856.
Há 1 dia · A number of arts events are held in Auckland, including the Auckland Festival, the Auckland Triennial, the New Zealand International Comedy Festival, and the New Zealand International Film Festival. The Auckland Philharmonia Orchestra is the city and region's resident full-time symphony orchestra, performing its own series of concerts and accompanying opera and ballet.
- Topography
- Types and Ratings of Rivers
- Ecosystem of Rivers
- Uses of Rivers
- Management of Rivers
- Concerns
- Further Reading
Source and drainage basin
A river begins at a source (or more often several sources) which is usually a watershed, drains all the streams in its drainage basin, follows a path called a rivercourse (or just course) and ends at either at a mouth or mouths which could be a confluence, river delta, etc. The water in a river is usually confined to a channel, made up of a stream bed between banks. In larger rivers there is often also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be very...
River channel
Rivers can flow down mountains, through valleys (depressions) or along plains, and can create canyons or gorges. The river channel typically contains a single stream of water, but some rivers flow as several interconnecting streams of water, producing a braided river. Extensive braided rivers are now found in only a few regions worldwide,[citation needed] such as the South Island of New Zealand. They also occur on peneplains and some of the larger river deltas. Anastamosing rivers are similar...
Rivers have been classified by many criteria including their topography, their biotic status, and their relevance to white water rafting or canoeingactivities.
River biota
The organisms in the riparian zone respond to changes in river channel location and patterns of flow. The ecosystem of rivers is generally described by the river continuum concept, which has some additions and refinements to allow for dams and waterfalls and temporary extensive flooding. The concept describes the river as a system in which the physical parameters, the availability of food particles and the composition of the ecosystem are continuously changing along its length. The food (ener...
River Chemistry
The chemistry of rivers is complex and depends on inputs from the atmosphere, the geology through which it travels and the inputs from man's activities. The chemical composition of the water has a large impact on the ecology of that water for both plants and animals and it also affects the uses that may be made of the river water. Understanding and characterising river water chemistry requires a well designed and managed sampling and analysis.
Construction material
The coarse sediments, gravel, and sand, generated and moved by rivers are extensively used in construction. In parts of the world this can generate extensive new lake habitats as gravel pits re-fill with water. In other circumstances it can destabilise the river bed and the course of the river and cause severe damage to spawning fish populations which rely on stable gravel formations for egg laying. In upland rivers, rapids with whitewater or even waterfalls occur. Rapids are often used for r...
Energy production
Fast flowing rivers and waterfalls are widely used as sources of energy, via watermills and hydroelectric plants. Evidence of watermills shows them in use for many hundreds of years, for instance in Orkney at Dounby Click Mill. Prior to the invention of steam power, watermills for grinding cereals and for processing wool and other textiles were common across Europe. In the 1890s the first machines to generate power from river water were established at places such as Cragside in Northumberland...
Food source
Rivers have been a source of food since pre-history. They are often a rich source of fish and other edible aquatic life, and are a major source of fresh water, which can be used for drinking and irrigation. Rivers help to determine the urban form of cities and neighbourhoods and their corridors often present opportunities for urban renewal through the development of foreshoreways such as river walks. Rivers also provide an easy means of disposing of waste waterand, in much of the less develop...
Rivers are often managed or controlled to make them more useful or less disruptive to human activity. 1. Dams or weirsmay be built to control the flow, store water, or extract energy. 2. Levees, known as dikes in Europe, may be built to prevent river water from flowing on floodplains or floodways. 3. Canals connect rivers to one another for water t...
Man-made causes, such as the over-exploitation and pollution, are the biggest threats and concerns which are making rivers ecologically deadand drying up the rivers. Plastic pollution imposes threats on aquatic life and river ecosystems because of plastic's durability in the natural environment. Plastic debris may result in entanglement and ingesti...
Jeffrey W. Jacobs. "Rivers, Major World". Rivers, Major World – dam, sea, effects, important, largest, salt, types, system, source. Water Encyclopaedia.Luna B. Leopold (1994). A View of the River. Harvard University Press. ISBN 978-0-674-93732-1. OCLC 28889034. — a non-technical primer on the geomorphology and hydraulicsof water.Middleton, Nick (2012). Rivers: a very short introduction. New York: Oxford University Press. ISBN 978-0-19-958867-1.Há 17 horas · Stock market highlights on Friday, July 26, 2024: Benchmarks Sensex and Nifty saw massive rallies on Friday, with the BSE Sensex climbing 1.62 per cent or 1292 points to end at 81,332 levels, while NSE’s Nifty50 closed 1.76 per cent or 428 points at 24,834 levels.
