Unit-II-Lesson-2-and-3.pdf

P a g e | 50 Hydrosphere is the discontinuous layer of water at or near Earth’s surface. It includes all liquid and frozen surface waters, groundwater held in soil and rock, and atmospheric water vapour. Wat...

P a g e | 50 Hydrosphere is the discontinuous layer of water at or near Earth’s surface. It includes all liquid and frozen surface waters, groundwater held in soil and rock, and atmospheric water vapour. Water is the most abundant substance at the surface of Earth. About 1.4 billion cubic km (326 million cubic miles) of water in liquid and frozen form make up the oceans, lakes, streams, glaciers, and groundwaters found there. It is this enormous volume of water, in its various manifestations, that forms the discontinuous layer, enclosing much of the terrestrial surface, known as the hydrosphere. How did the hydrosphere evolve? It is not very likely that the total amount of water at Earth’s surface has changed significantly over geologic time. Based on the ages of meteorites, Earth is thought to be 4.6 billion years old. The oldest rocks known are 3.9 billion to 4.0 billion years old, and these rocks, though altered by post-depositional processes, show signs of having been deposited in an environment containing water. There is no direct evidence for water for the period between 4.6 billion and 3.9–4.0 billion years ago. Thus, ideas concerning the early history of the hydrosphere are closely linked to theories about the origin of Earth.  P a g e | 51 Water, a substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states. It is one of the most plentiful and essential of compounds. A tasteless and odourless liquid at room temperature, it has the important ability to dissolve many other substances. Indeed, the versatility of water as a solvent is essential to living organisms. Life is believed to have originated in the aqueous solutions of the world’s oceans, and living organisms depend on aqueous solutions, such as blood and digestive juices, for biological processes. Water also exists on other planets and moons both within and beyond the solar system. In small quantities water appears colourless, but water actually has an intrinsic blue colour caused by slight absorption of light at red wavelengths. Structure of Water The water molecule is composed of two hydrogen atoms, each linked by a single chemical bond to an oxygen atom. Most hydrogen atoms have a nucleus consisting solely of a proton. Two isotopic forms, deuterium and tritium, in which the atomic nuclei also contain one and two neutrons, respectively, are found to a small degree in water. Deuterium oxide (D2O), called heavy water, is important in chemical research and is also used as a neutron moderator in some nuclear reactors. A water molecule is made up of two hydrogen atoms and one oxygen atom. A single oxygen atom contains six electrons in its outer shell, which can hold a total of eight electrons. When two hydrogen atoms are bound to an oxygen atom, the outer electron shell of oxygen is filled. Physical Properties of Water Water has several important physical properties. Although these properties are familiar because of the omnipresence of water, most of the physical properties of water are quite atypical. Given the low molar mass of its constituent molecules, water has unusually large values of viscosity, surface tension, heat of vaporization, and entropy of  P a g e | 52 vaporization, all of which can be ascribed to the extensive hydrogen bonding interactions present in liquid water. The open structure of ice that allows for maximum hydrogen bonding explains why solid water is less dense than liquid water—a highly unusual situation among common substances. Process of Water Cycle Earth's water is always in movement, and the natural water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the blink of an eye and over millions of years. Where does all the Earth's water come from? Primordial Earth was an incandescent globe made of magma, but all magmas contain water. Water set free by magma began to cool down the Earth's atmosphere, until it could stay on the surface as  P a g e | 53 a liquid. Volcanic activity kept and still keeps introducing water in the atmosphere, thus increasing the surface- and groundwater volume of the Earth. The water cycle has no starting point. But, we'll begin in the oceans, since that is where most of Earth's water exists. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air. Ice and snow can sublimate directly into water vapor. Rising air currents take the vapor up into the atmosphere, along with water from evapotranspiration, which is water transpired from plants and evaporated from the soil. The vapor rises into the air where cooler temperatures cause it to condense into clouds. Air currents move clouds around the globe, cloud particles collide, grow, and fall out of the sky as precipitation. Some precipitation falls as snow and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Snowpacks in warmer climates often thaw and melt when spring arrives, and the melted water flows overland as snowmelt. Most precipitation falls back into the oceans or onto land, where, due to gravity, the precipitation flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, with streamflow moving water towards the oceans. Runoff, and groundwater seepage, accumulate and are stored as freshwater in lakes. Not all runoff flows into rivers, though. Much of it soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes aquifers (saturated subsurface rock), which store huge amounts of freshwater for long periods of time. Some infiltration stays close to the land surface and can seep back into surface-water bodies (and the ocean) as groundwater discharge, and some groundwater finds openings in the land surface and emerges as freshwater springs. Over time, though, all of this water keeps moving, some to re-enter the ocean, where the water cycle "ends" or “starts” all over again.  P a g e | 54 The ocean is a continuous body of salt water that covers more than 70 percent of the Earth's surface. Ocean currents govern the world's weather and churn a kaleidoscope of life. Humans depend on these teeming waters for comfort and survival, but global warming and overfishing threaten Earth's largest habitat. Geographers divide the ocean into five major basins: the Pacific, Atlantic, Indian, Arctic, and Southern. Smaller ocean regions such as the Mediterranean Sea, Gulf of Mexico, and the Bay of Bengal are called seas, gulfs, and bays. Inland bodies of saltwater such as the Caspian Sea and the Great Salt Lake are distinct from the world's oceans. The oceans hold about 321 million cubic miles (1.34 billion cubic kilometers) of water, which is roughly 97 percent of Earth's water supply. Seawater's weight is about 3.5 percent dissolved salt; oceans are also rich in chlorine, magnesium, and calcium. The oceans absorb the sun's heat, transferring it to the atmosphere and distributing it around the world. This conveyor belt of heat drives global weather patterns and helps regulate temperatures on land, acting as a heater in the winter and an air conditioner in the summer. Sea Life The oceans are home to millions of Earth's plants and animals—from tiny single-celled organisms to the gargantuan blue whale, the planet's largest living animal. Fish, octopuses, squid, eels, dolphins, and whales swim the open waters while crabs, octopuses, starfish, oysters, and snails crawl and scoot along the ocean bottom.  P a g e | 55 Life in the ocean depends on phytoplankton, mostly microscopic organisms that float at the surface and, through photosynthesis, produce about half of the world's oxygen. Other fodder for sea dwellers includes seaweed and kelp, which are types of algae, and seagrasses, which grow in shallower areas where they can catch sunlight. The deepest reaches of the ocean were once thought to be devoid of life, since no light penetrates beyond Hydrothermal Vents 1,000 meters (3,300 feet). But then hydrothermal vents were discovered. These chimney-like structures allow tube worms, clams, mussels, and other organisms to survive not via photosynthesis but chemosynthesis, in which microbes convert chemicals released by the vents into energy. Bizarre fish with sensitive eyes, translucent flesh, and bioluminescent lures jutting from their heads lurk about in nearby waters, often surviving by eating bits of organic waste and flesh that rain down from above, or on the animals that feed on those bits. Despite regular discoveries about the ocean and its denizens, much remains unknown. More than 80 percent of the ocean is unmapped and unexplored, which leaves open the question of how many species there are yet to be discovered. At the same time, the ocean hosts some of the world's oldest creatures: Jellyfish have been around more than half a billion years, horseshoe crabs almost as long. Permanent ice zone is a region that is covered with sea ice year-round; most of the sea ice in the permanent ice zone is multiyear ice, but younger ice and open water may still be present; the permanent ice zone is what remains in summer after all melting has occurred (often called the summer minimum extent).  P a g e | 56 Location and climate: You can find this permanent ice biome in Greenland and Antarctica, but also includes this Biome the polar masses and large polar ice caps of the Arctic. The permanent ice is a very cold biome, at the Antarctica has recorded a temperature as low as 89 Celsius. The winter temperature for example at the Arctic is -30 Celsius. The most time it fall snow in this Biome. The annual precipitation per year is 50cm, but most falling as snow. Physical features: The permanent ice is one of the coldest biomes and this is all year-round. One physical feature is the very strong and cold wind. Because of the freezing conditions a little fresh water available. Another physical feature is the little soil. In the Arctic there are more than 100 of flowering, but in the Antarctica there are only two plants who can survive, because of its brief growing season. One of them is Lichens. Lichens are a composite organism consisting of a fungus and a photosynthetic. They survive in the cold area because they operate even far below the freezing point of photosynthesis. Another plant who can survive in the permanent ice biome is the Pasque flower. This plant ranges throughout the northwestern United States and up to northern Alaska. Its covering is of fine silky hairs that provides insulation. Animal adaptation: There are a lot of animals in the permanent ice biome, one of them is the polar bear. The Polar bears have a thick layer of fat and a thick layer of white fur. They also have small ears, large body, sharp claws and teeth, strong legs and large feet with fur on the soles. These features enable them to adequately adapt to their environment.  P a g e | 57 `Another animal is the Walrus Living in the Arctic is not hard for the walrus to do because they have blubber under their skin. Blubber is their body fat. This protects them from the cold water in the Arctic. Facts about Glaciers Presently, 10 percent of land area on Earth is covered with glacial ice, including glaciers, ice caps, and the ice sheets of Greenland and Antarctica. Glacierized areas cover over 15 million square kilometers (5.8 million square miles). Glaciers store about 69 percent of the world's fresh water. During the maximum point of the last ice age, glaciers covered about 32 percent of the total land area. Starting around the early 14th century, and lasting to the mid-19th century, the world experienced a “Little Ice Age,” when temperatures were consistently cool enough for glaciers to advance in many areas of the world. In the United States, glaciers cover over 90,000 square kilometers (35,000 square miles). Most of those glaciers are located in Alaska, which holds 87,000 square kilometers (34,000 square miles) of glacial ice. The largest glacier in the world is the Lambert-Fisher Glacier in Antarctica. At 400 kilometers (250 miles) long, and up to 100 kilometers (60 miles) wide, this ice stream alone drains about 8 percent of the Antarctic Ice Sheet. Antarctic ice is up to 4.7 kilometers (3 miles) thick in some areas. Antarctic ice shelves may calve icebergs that are over 80 kilometers (50 miles) long. The Antarctic continent has been at least partially covered by an ice sheet for the past 40 million years.  P a g e | 58 Water is generally classified into two groups: surface water and groundwater. In general: Groundwater is located underground in large aquifers and must be pumped out of the ground after drilling a deep well. Surface water is found in lakes, rivers and streams and is drawn into the public water supply by an intake. Surface water is just what the name implies; it is water found in a river, lake or other surface cavity. This water is usually not very high in mineral content, and is often called “soft water” even though it is probably not. Surface water is exposed to many different contaminants, such as animal wastes, pesticides, insecticides, industrial wastes, algae and many other organic materials. Even surface water found in what seems like pristine mountain streams can be contaminated by wild animal waste, dead animals upstream or other decay. Groundwater is water contained in or by a subsurface layer of soil or rock. There are many sources recharging the supply of groundwater, including rain that soaks into the ground, rivers that disappear underground and melting snow. Because of the many sources of recharge, groundwater may contain any or all of the contaminants found in surface water as well as the dissolved minerals it picks up underground. However, groundwater commonly contains less contamination than surface water because the rock tends to act as a filter to remove some contaminants. Imagine that rain falls and the rainwater soaks into the ground. The plants use as many nutrients as they can and then the water continues to filter down through clay, sand and porous rock filtering the water much like a charcoal filter might clean your drinking water at home. Eventually this groundwater finds a home in an aquifer or trapped between levels of rock creating a water table. This is the water you most often drink from your well. Due to the minerals picked up while filtering through the rocks, groundwater is typically considered to be “hard” water.  P a g e | 59 How is the distribution and quantity of Earth’s waters? Ocean waters and Water Masses at the Earth's Surface waters trapped in the pore reservoir volume (in cubic percent of total spaces of sediments make up kilometres) most of the present-day oceans 1,338,000,000 96.5 hydrosphere. The total mass of ice caps, glaciers, 24,064,000 1.74 water in the oceans equals and permanent snow about 50 percent of the mass of ground ice and 300,000 0.22 sedimentary rocks now in permafrost existence and about 5 percent of groundwater 23,400,000 1.69 the mass of Earth’s crust as a (total) whole. Deep and shallow groundwater 10,530,000 0.76 (fresh) groundwaters constitute a small groundwater 12,870,000 0.93 percentage of the total water (saline) locked in the pores of lakes (total) 176,400 0.013 sedimentary rocks—on the lakes (fresh) 91,000 0.007 order of 3 to 15 percent. The lakes (saline) 85,400 0.006 amount of water in the soil moisture 16,500 0.001 atmosphere* 12,900 0.001 atmosphere at any one time is swamp water 11,470 0.0008 trivial, equivalent to roughly rivers 2,120 0.0002 13,000 cubic km (about 3,100 biota 1,120 0.0001 cubic miles) of liquid water, or total** 1,409,560,910 101.67 about 0.001 percent of the total *As liquid equivalent of water vapour. at Earth’s surface. This water, **Total surpasses 100 percent because of upward rounding of individual reservoir volumes. however, plays an important role in the water cycle. Source: Adapted from Igor Shiklomanov's chapter "World Fresh Water Resources" in Peter H. Gleick (ed.), Water in Crisis: A Guide to the World's At present, ice locks up Fresh Water Resources, copyright 1993, Oxford University Press, New York, a little more than 2 percent of N.Y. Tablemade available by the United States Geological Survey. Earth’s water and may have accounted for as much as 3 percent or more during the height of the glaciations of the Pleistocene Epoch (2.6 million to 11,700 years ago). Although water storage in rivers, lakes, and the atmosphere is small, the rate of water circulation through the rain-river-ocean-atmosphere system is relatively rapid. The amount of water discharged each year into the oceans from the land is approximately equal to the total mass of water stored at any instant in rivers and lakes. Soil moisture accounts for only 0.005 percent of the water at Earth’s surface. It is this small amount of water, however, that exerts the most direct influence on evaporation from soils. The biosphere, though primarily H2O in composition, contains very little of the total water at the terrestrial surface, only about 0.00004 percent, yet the biosphere plays a major role in the transport of water vapour back into the atmosphere by the process of transpiration.  P a g e | 60 Water Word Instruction: Find the words hidden in the puzzle. Words may be hidden horizontally, vertically, or diagonally.  P a g e | 61 The lithosphere is derived from the word “sphere,” combined with the Greek word “lithos” which means rock. The lithosphere is the rocky outer part of the Earth. It is made up of the brittle crust and the top part of the upper mantle. The lithosphere is the coolest and most rigid part of the Earth. The lithosphere extends from the surface of Earth to a depth of about 44-62 mi (70-100 km). The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth’s structure. It is bounded by the atmosphere above and the asthenosphere (another part of the upper mantle) below. Although the rocks of the lithosphere are still considered elastic, they are not viscous. he asthenosphere is viscous, and the lithosphere-asthenosphere boundary (LAB) is the point where geologists and rheologists—scientists who study the flow of matter— mark the difference in ductility between the two layers of the upper mantle. Ductility measures a solid material’s ability to deform or stretch under stress. The lithosphere is far less ductile than the asthenosphere. There are two types of lithosphere: oceanic lithosphere (left) and continental lithosphere (right). Oceanic lithosphere is associated with oceanic crust, and is slightly denser than continental lithosphere.  P a g e | 62 Earth’s surface is an amazing place to behold. Yet even the deepest canyon is but a tiny scratch on the planet. To really understand Earth, you need to travel 6,400 kilometers (3,977 miles) beneath our feet. Starting at the center, Earth is composed of four distinct layers. They are, from deepest to shallowest, the inner core, the outer core, the mantle and the crust. Except for the crust, no one has ever explored these layers in person. In fact, the deepest humans have ever drilled is just over 12 kilometers (7.6 miles). And even that took 20 years! A cut-away of Earth’s layers reveals how thin the crust is when compared to the lower layers. Starting at the center, Earth is composed of four distinct layers. They are, from deepest to shallowest, the inner core, the outer core, the mantle and the crust. Except for the crust, no one has ever explored these layers in person. In fact, the deepest humans have ever drilled is just over 12 kilometers (7.6 miles). And even that took 20 years! Still, scientists know a great deal about Earth’s inner structure. They’ve plumbed it by studying how earthquake waves travel through the planet. The speed and behavior of these waves change as they encounter layers of different densities. Scientists — including Isaac Newton, three centuries ago — have also learned about the core and mantle from calculations of Earth’s total density, gravitational pull and magnetic field. Here’s a primer on Earth’s layers, starting with a journey to the center of the planet. The inner core This solid metal ball has a radius of 1,220 kilometers (758 miles), or about three-quarters that of the moon. It’s located some 6,400 to 5,180 kilometers (4,000 to 3,220 miles) beneath Earth’s surface. Extremely dense, it’s made mostly of iron and nickel. The inner core spins a bit faster than the rest of the planet. It’s also intensely hot: Temperatures sizzle at 5,400° Celsius (9,800° Fahrenheit). That’s almost as hot as the  P a g e | 63 surface of the sun. Pressures here are immense: well over 3 million times greater than on Earth’s surface. Some research suggests there may also be an inner, inner core. It would likely consist almost entirely of iron. The earth’s crust is the layers of Earth on which occur all forms of life occur by humans. The crust is relatively thin and has probably been recycled and destroyed by strong tectonic movements and impacts of asteroids that were common in the early solar system. The crust is located at the top of the lithosphere with a thickness of 3 km (2 miles) and up to 100 km (60 miles). The average density in the upper crust is between 2.69 tons/m3 and 2.74 tons/m3 and the lower crust between 3 and 3.2 tons/m3. The Earth’s crust is composed of a variety of igneous, metamorphic and sedimentary rocks like basalts and granites although on average can be said to be composed of a material similar to the andesite (volcanic extrusive igneous rock with about 60% of dioxides of silicon SiO2 and other minerals) and is enriched with incompatible elements with basaltic or volcanic ocean compared to the mantle.  P a g e | 64 Regarding elements, the crust is made up of oxygen-O (45%), silicon-Si (27%), aluminum-Al (8%), iron Fe (6%), calcium-Ca (5%) , sodium-Na (3%), potassium-K (2%),magnesium (3%), titanium (1%) totaling 98.9% of the crust and other scarce elements. Regarding compounds, it is estimated that the surface of the crust has a composition of 61% silicon oxide (SiO2), 16% aluminum oxide (Al2O2), 7% iron oxide (FeO), 6% calcium oxide (CaO), 5% magnesium oxide (MgO), 3% sodium oxide (Na2O), 2% potassium oxide (K2O) and 1% titanium oxide (TiO2). The temperature of the crust increases with depth reaching values of up to 200 ° C and 400 ° C at the edge of the upper mantle. The temperature rises to 30 ° C for each kilometer of depth on the crust. The rock cycle is a series of processes that create and transform the types of rocks in Earth’s crust. The rock cycle is driven by two forces: (1) Earth’s internal heat engine, which moves material around in the core and the mantle and leads to slow but significant changes within the crust, and (2) the hydrological cycle, which is the movement of water, ice, and air at the surface, and is powered by the sun. Rocks can be classified into three: igneous, metamorphic and sedimentary. These different rock types can be transformed into one another. Sedimentary rock can become igneous, metamorphic or another sedimentary rock, metamorphic rock can become igneous, sedimentary or another metamorphic rock and igneous rock can become sedimentary, metamorphic or another igneous rock.  P a g e | 65 The cycle starts when magma cools. Magma is a hot liquid made of melted minerals. This cooling of magma forms the igneous rock. Igneous rock can form underground, where the magma cools slowly or it can form above ground, where the magma cools quickly. When they are formed inside of the earth, they are called intrusive or plutonic igneous rocks. If they are formed outside or on top of Earth’s crust, they are called extrusive or volcanic igneous rocks. On Earth's surface, wind and water can break rocks into pieces. They can also carry rock pieces to another place. Usually, the rock pieces, called sediments, drop from the wind or water to make a layer. The layer can be buried under other layers of sediments. After a long time the sediments can be cemented together to make sedimentary rock. There are three different types of sedimentary rocks: clastic, organic (biological), and chemical. Clastic sedimentary rocks, like sandstone, form from clasts, or pieces of other rock. Organic sedimentary rocks, like coal, form from hard, biological materials like plants, shells, and bones that are compressed into rock while chemical sedimentary rocks, like limestone, halite, and flint, form from chemical precipitation. Rocks can also be subjected to immense heat coming from the pressure inside the earth. When igneous and sedimentary rocks are exposed to heat, it changes into a metamorphic rock. Metamorphic rocks have two classes: foliated and non-foliated. When a rock with flat or elongated minerals is put under immense pressure, the minerals line up in layers, creating foliation. Foliation is the aligning of elongated or platy minerals, like hornblende or mica, perpendicular to the direction of pressure that is applied. An example of this transformation can be seen with granite, an igneous rock. Granite contains long and platy minerals that are not initially aligned, but when enough pressure is added, those minerals shift to all point in the same direction while getting squeezed into flat sheets. When granite undergoes this process, like at a tectonic plate boundary, it turns into gneiss.  P a g e | 66 Non-foliated rocks are formed the same way, but they do not contain the minerals that tend to line up under pressure and thus do not have the layered appearance of foliated rocks. Sedimentary rocks like bituminous coal, limestone, and sandstone, given enough heat and pressure, can turn into non-foliated metamorphic rocks like anthracite coal, marble, and quartzite. Non-foliated rocks can also form by metamorphism, which happens when magma comes in contact with the surrounding rock.  P a g e | 67 Water Word Instruction: Fill out the diagram below with the type of rock that is formed from the following process.  P a g e | 68 Reference Materials https://sciencebiomes10.weebly.com/permanent-ice.html https://nsidc.org/cryosphere/glaciers/quickfacts.html http://residential.goulds.com/spring-run-off-the-difference-between-surface-water-and groundwater/#:~:text=In%20general%3A%20Groundwater%20is%20located,water%20s upply%20by%20an%20intake.&text=Groundwater%20is%20water%20contained%20in,l ayer%20of%20soil%20or%20rock. http://www.artinaid.com/2013/04/composition-of-the-earths-crust/