Spheres of the Earth PDF - BSc Hons in Social Studies

SPHERES OF THE EARTH BACHELORS OF SCIENCES HONS IN SOCIAL STUDIES IN INDIGENOUS KNOWLEDGE BSSI 11033 FIRST YEAR FIRST SEMESTER Ms. Dhanushika Pilapitiya...

SPHERES OF THE EARTH BACHELORS OF SCIENCES HONS IN SOCIAL STUDIES IN INDIGENOUS KNOWLEDGE BSSI 11033 FIRST YEAR FIRST SEMESTER Ms. Dhanushika Pilapitiya B.A. (Sp) in Geography, M.Sc. In Geoinformatics (Reading) Department of Indigenous Social Sciences Faculty of Indigenous Social Sciences and Management Studies 1 GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE ©  LEARNING OUTCOMES  Understand the Earth’s different spheres.  Identify the each spheres’ Characteristics. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 2  INTRODUCTION  Everything in earth’s system is placed into several subsystems.  Those subsystems are known as spheres.  “Sphere” is a Greek term which means ball.  Specifically they are known as Geosphere (land) Hydrosphere (Water) Biosphere (Living things) Atmosphere (Air) GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 3   These spheres are so closely connected to each other.  So, one change in a sphere often results in a change in one or more of the other spheres.  Interaction also occur among spheres. For example: Hydrosphere and Atmosphere: The evaporation that occurs in the hydrosphere forms the medium for cloud and rain formation in the atmosphere GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 4 GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 5  GEOSPHERE  The earth's minerals and rocks, from molten rock and heavy metals deep within the planet to sand on beaches and mountain tops, are collectively referred to as the geosphere.  The abiotic (non-living) components of soils and animal bones that could become fossilized throughout geologic time are also included in the geosphere.  The Geosphere is associated with solid portions of the Earth.  It comprises all other layers of the Earth's interior as well as the crusts of the oceans and continents.  The Earth System interacts with the Geosphere in the following ways: GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 6 GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 7   Rock Cycle also a process which happens in this geosphere. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 8   The movement of Earth's tectonic plates, which produces mountains, volcanoes, and ocean basins, is the main force behind these activities.  Variations in the creation and destruction rates of rocks can have a significant impact on the Earth.  Over geologic time spans, the rate of plate tectonic movements has altered, resulting in changes to the rock cycle that have an impact on the climate.  For instance, there has been increased volcanic activity during periods of significant plate movement, which releases more particles into the atmosphere. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 9   More mountains are formed in regions where plates converge as a result of faster plate tectonic movements.  When rocks are pushed upward to form mountains, they begin to erode and disintegrate, releasing nutrients and sediments into streams. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 10  THE STRUCTURE O THE GEOSPHERE GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 11  THE STRUCTURE O THE GEOSPHERE - CRUST  The outermost layer of the earth.  It is just like a peal of an apple.  Very thin layer.  The crust varies in thickness, but it is only rarely more than about 50 km thick, which is nothing compared to the nearly 6370 km to earth’s very center.  However, with its mountains, valleys, continents, ocean bottoms, and other features, this thin, microscopic layer is what we refer to as "the earth".  Because of its modest density (2.5 to 3.5 gm/cm3), the crust can float on top of the mantle's higher density.  Like the crusts of many other planets, the crust of Earth is fragile and fractures readily.  There are actually two types of crust, continental and oceanic. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 12  Massive granite boulders, volcanic lava flows, and sediments deposited in shallow water or continental seas make up the continental crust.  It is fairly thick, extending below sections of 80-kilometer mountain ranges and averaging 30 to 40 kilometers.  However, it is composed of rocks with lesser densities, such granite and andesite. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 13  The shallow, barely 5 to 10 km deep oceanic crust is composed of relatively thick basalt rock, which may be covered in gabbro, a similar-grained but coarser rock.  It also has a higher percentage of magnesium in it.  Although the bottom crust's composition is unknown, gabbro is most likely its makeup.  It is penetrated by seismic waves more quickly than the top crust.  The sharp boundary between the crust and mantle is called the Mohorovičić discontinuity or Moho. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 14  THE STRUCTURE O THE GEOSPHERE - MANTLE  The mantle is a complicated intermediate zone that lies under the crust.  Mantle is the widest section of the Earth.  Between the molten core and the crust is a wide layer of hard rock and metal oxides.  The mantle makes up around 82% of the Earth's volume and reaches a depth of about 2900 km.  It is believed that peridotite, a form of rock consisting of iron, magnesium, silicon, and oxygen, makes up the majority of the mantle.  The reason behind the plates of the Earth moving is the movement of the mantle. Its temperature varies between 1600 Fahrenheit at the upper part to 4000 Fahrenheit near the bottom.  Gutenberg discontinuity seperates the mantle from the core. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 15  THE STRUCTURE O THE GEOSPHERE - CORE  It is both the Earth's center and its hottest layer.  The core is composed of mostly iron and nickel and remains very hot, even after 4.5 billion years of cooling.  Unlike the mineral-rich crust and mantle, the core is made almost entirely of metal— specifically, iron (Fe) and nickel (Ni).  Another key element in Earth’s core is sulfur—in fact 90 percent of the sulfur on Earth is found in the core. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 16  The fluctuating temperatures in the core depend on pressure, Earth's rotation, and the varying composition of core elements.  In general, temperatures range from about 4,400° Celsius (7,952° Fahrenheit) to about 6,000° Celsius (10,800° Fahrenheit).  The core is made of two layers: the outer core, which borders the mantle, and the inner core.  The boundary separating these regions is called the Bullen discontinuity.  The outer core, about 2,200 kilometers (1,367 miles) thick, is mostly composed of liquid iron and nickel.  The outer core is very hot, between 4,500° and 5,500° Celsius (8,132° and 9,932° Fahrenheit). GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 17  The inner core is a hot, dense ball of (mostly) iron.  It has a radius of about 1,220 kilometers (758 miles).  Temperature in the inner core is about 5,200° Celsius (9,392° Fahrenheit).  The inner core's temperature is far higher than iron's melting point.  The inner core, however, is neither liquid or even molten, in contrast to the outer core.  The iron is kept from melting by the extreme pressure of the planet's inner core, which encompasses the entire planet and its atmosphere. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 18 ACTIVITY  Prepare a note on the topic “The structure of the geosphere”.  Submit it on or before 4.00 p.m. 11th of May 2024.  No word Limit  You can either write or type. GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 19  TO BE CONTINUED….. Thank you GAMPAHA WICKRAMARACHCHI UNIVERSITY OF INDIGENOUS MEDICINE © 20