Online assignment preethui
- 1. ONLINE ASSIGNMENT Topic : Identification of Natural Resources for Science Teaching and Learning – “SEA” Submitted to : Sreekala Mam Natural Science Submitted by: Preethi.P.S Natural Science Submitted on 06/11/2015
- 2. Topic: Identification of Natural resources for Science Teaching and Learning –“SEA” INTRODUCTION Natural resources-occur naturally within environments that exists relatively undisturbed by humanity in a natural form. A natural resource is often characterized by amounts of biodiversity and geodiversity existent in various ecosystems. Natural resources are derived from the environment. Some of them are essential for our survival while most are used for satisfying our needs. Natural resources are materials and components that can be found with the environment natural resources may exist as a separate entity such as fresh water, and air, as well as a living organism. Such as a fish or it may exist is an alternate form which must be processed to obtain the resource such as metal ores, oil and most forms of energy. SEA A sea is a large body of salt water that is surrounded in whole part by land more broadly the sea is the interconnected system of the Earth’s salty, oceanic waters considered as one global ocean or as several principal oceanic divisions. The sea moderates the Earth’s climate and has important roles of the water cycle, carbon cycle and nitrogen cycle. The sea is conventionally divided into up to five large oceanic sections named the Atlantic, Pacific, Indian and Artic.
- 3. Seas are essential for human development and trade, travel, mineral extraction and power generation. This has also made it essential to warfare and left major cities exposed to earthquakes and volcanoes from nearby faults, powerful tsunami waves, and hurricanes, typhoons and cyclones produced in the tropics. It is the scene of leisure activities including swimming diving, surfing and sailing. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a process known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem. Owing to the present state of continental drift, the Northern Hemisphere is now fairly equally divided between the land and sea. But the south in overwhelmingly oceanic about 85% of the solids in the open sea are sodium chloride. Former changes in the sea levels have left continental shelves, shallow areas in the sea closed to land. These nutrient. Rich waters team with life, which provide humans with substantial supplies of food-mainly fish, but also shell fish, mammals, and seaweed which are both harvested in the wild and farmed. Both plants and animals first evolved in the sea. There are no sharp distinction between seas and oceans. Seas are generally larger than lakes and contain salt water. , but the sea of Galilee is a fresh water lake. In International laid, the united nations convention on the law the sea slates that all the ocean is the sea”
- 4. Earth is the only known planet with a seas of liquid water on its surface it is still unclear where Earth’s water came from but seen from space, our planet appears as a “blue marble” of its various forms, ice caps, clouds. The underground reservoir various states of the water cycles, containing the fresh water encountered and used by most terrestrial life, vapour is the air, the cloud it slowly forms, the rain falling from them, and the lakes and rivers spontaneously formed as its waters flow again and again to the sea. Sea water is invariably salty and although its degree of saltiness can vary, about 90% of the water in the ocean has 34-35 of dissolved solids per liter, producing salinity between 3.4 and 3.5%. the solutes in ocean water come both from inflowing river water and from the ocean floor. Sodium and chloride make up about 85% other soltes include metal ions such as magnesium and calcium and native ions such as magnesium and calcium and negative ions such as sulfate, carbonate and bromides. In the absence of other pollution, sea water would not be harmful to drink except that it is much too saline, similarly, it cannot be used for irrigating most plants without being desalinated. For scientific and technical purposes a standardized form of artificial seawater in often used. MEAN SURFACE TEMPERATURE:- Sea Temperature chiefly depends on the amount of solar radiation it absorbs. In the tropics where sunlight falls more directly, the temperature of the surface layers can
- 5. to over 30oc. the Cold Water is the deep sea moves back towards the equator before welling up again to the surface. Deep seawater has a temperature between 2nd 5oc. MEAN SURFACE OXYGEN LEVELS. The amount of oxygen present is seawater depends primarily upon its temperature and the photosynthetic organism living in it, particularly algae, phytoplankton and plants such as sea grass. During the day, their photosynthetic activity produces oxygen, which dissolves into the water’s oxygen saturation is lower during the night and much lower in the deep sea. Below as depth of about 200m there is insufficient light for photosynthesis and consequently little dissolved oxygen. Below the anaerobic bacteria break down falling organic material, producing hydrogen sulfide. It is projected that global warming will reduce oxygen both in surface and deep water due to oxygen’s decreased solubility as temperature increase and increased oceanic stratification. WEAVES. Ocean surface waves are oscillations caused by the friction from air moving across the surface of the water. This friction transfers energy and forms surface waves in the water perpendicular to the direction of the wind. The top of a wave is known as its crest and its foot as its trough, the distance between two crests in the wavelength. The smallest waves are called ripples.
- 6. A tsunami is a an unusual from of wave caused by a sudden and powerful event such as an underwater earthquake or landslide, a meteorite impact, a volcanic eruption, or a collapse of land into the sea. Tsunami warning systems rely on the fact that seismic waves caused by earthquakes travel around the world at around 14,400 kilometers per hour, allowing threatened regions to be alerted to the possibility of a tsunami. Tides are the regular rise and fall in water level experienced by seas and oceans in response to the gravitation influences of the moon and the sun, and the effects of the earth’s rotation. At any given place, the water rises over the course of the today cycle to a maximum height known as “high tide” before ebbing away again to a minimum “low tide” level. The difference in height between the high tide and low tide is known as the tidal range or tidal amplitude. Bathymetry is the mapping and study of the topography of the ocean floor Methods used for measuring the depth of the sea include single or multi bean echosounders, laser aiborne depth sounders and the calculation depths from satellite remote sensing data. The earth’s deepest trench is the Marina trench which extends for about 2,500 kilometers across the seabed. It is near the Marina Islands, a volcanic archipelago in the west pacific though ti averages just 68km wide its deepest point is 10,994 kilometers below the surface of the sea.
- 8. CONCLUSION Sea is a large body of salt water that is surrounded in whole or is part by land, the sea is conventionally divided into up to five large oceanic sections named the Atlantic, pacific, Indian and Artic. Seas are essential for human developed and trade, travel, mineral extraction and power generation. There are no sharp distinctions between seas and oceans. Seas are generally layer than lakes and contain salt water. In the absence of other pollution, sea water would not harmful to drink except that it is much too saline. For scientific and technical purposes a standardized form of artificial seawater is often used.
- 9. REFERENCES. 1. Reddy M.P.M.; Descriptive physical oceanography, Balkemia, Leiden (2001) 2. Nishri.A; Stiller.M; Rimmer.A, Lake Kinneret, Chemical Geology (1999) 3. Vikas, B; The Law of the Sea; Selected writings (2004). 4. Murakami.M, “Water in Earth’s lower Mantle”, (2002)