Earth Science Senior High School Carmen, Agus. Del Norte PDF

SENIOR HIGH SCHOOL IN CARMEN, AGUSAN DEL NORTE Earth Science https://youtu.be/G4nDcczMoBw?t=521 MELC’s Describe how rocks undergo weathering (MELC S11ES-IIa-22) Weathering is the breaking down of rocks either mechanically or chemically. Factors that cause wea...

SENIOR HIGH SCHOOL IN CARMEN, AGUSAN DEL NORTE Earth Science https://youtu.be/G4nDcczMoBw?t=521 MELC’s Describe how rocks undergo weathering (MELC S11ES-IIa-22) Weathering is the breaking down of rocks either mechanically or chemically. Factors that cause weathering of rocks are: 1. climate 2. surface area and topographic relief 3. rock composition Two types of Weathering: 1. Physical (or mechanical) Weathering a process wherein rocks are broken down into smaller pieces without changing their chemical composition due to several factors like fluctuating temperatures and pressure, and biological activity. the processes that lead to the mechanical disintegration of rocks include frost wedging, salt crystal growth, abrasion and biological activity. Frost wedging is when water gets inside the joints, alternate freezing and thawing episodes pry the rock apart. Picture 1 is an example of frost wedging in which water entering cracks in rock expands upon freezing, forcing the cracks to widen; this process is also known as frost shattering and it is extremely effective in areas that regularly fluctuate around 0 degree Celsius, such as high mountains in temperate climates and in polar regions. https://www.pinterest.ph/pin/524810162810125467/ Picture 2 is an example of salt crystal growth; this is when force exerted by salt crystal that formed as water evaporates from pore spaces or cracks in rocks can cause the rock to fall apart. Abrasion is the wearing away of rocks by constant collision of loose particles. This happens when rocks are broken down into smaller fragments and are carried away with wind and water. Biological activity is when plants and animals act as agents of mechanical weathering.  2. Chemical Weathering is a process wherein rock materials are changed into other substances that have different physical and chemical compositions. there are three major processes of chemical weathering: dissolution, oxidation and hydrolysis. Dissolution is the process whereby a mineral dissolves in a solvent as a result of the freeing up of its ions. Therefore dissolution occurs when an action of slightly acidic solutions on the rock leaves pits and holes, which can slowly enlarge and widen preexisting fractures. Common example includes dissolution of calcite and salt. https://www.amnh.org/explore/ology/earth/if-rocks- Oxidation is the reaction between minerals and oxygen dissolved in water often giving iron-rich rocks a rusty-colored weathered surface. Hydrolysis is the chemical breakdown of a substance when combined with water MELC’s Explain why the earth’s interior is hot (MELCS11ES-IIb-c-23) How hot is the Earth’s Interior? The table in the succeeding slide will help you visualize and understand the composition and structure of the Earth’s interior. It provides you scientific knowledge that will help you describe the different layers of the Earth as well as understand their characteristics.  Scientist tried to explore and study the interior of the Earth. Yet, until today, there are no mechanical probes or actual explorations done to totally discover the deepest region of the Earth. We will explore and dig into the interiors of the Earth from the outer most layer which is the crust, then the mantle and finally the core- outer core and inner core. Out from these layers, you will try to discover how heat inside the planet is produced and its importance to the existence of all living beings. Sources of Earth’s Internal Heat Convection is one of the reasons of the heat in the earth’s interior. The process tells us that the heat in the earth’s internal is redistributed. The less dense material rises and more dense material sinks. Convection occurs at the upper mantle where hot rock rises and slightly cooler rock sinks. The heat driving mantle convection has three main sources namely: 1. Primordial Heat  The general term for the heat imparted to a planetary body by the processes of its formation and differentiation. It has three major components: A. Accretional heat: This is the heat generated by the conversion of the kinetic energy of impacting bodies to thermal energy. It is concentrated at the surface. Sources of Earth’s Internal Heat Convection is one of the reasons of the heat in the earth’s interior. The process tells us that the heat in the earth’s internal is redistributed. The less dense material rises and more dense material sinks. Convection occurs at the upper mantle where hot rock rises and slightly cooler rock sinks. The heat driving mantle convection has three main sources namely: 1. Primordial Heat  The general term for the heat imparted to a planetary body by the processes of its formation and differentiation. It has three major components: A. Accretional heat: This is the heat generated by the conversion of the kinetic energy of impacting bodies to thermal energy. It is concentrated at the surface. B. Gravitational release: The gravitational potential of dense materials is converted to heat during differentiation. As iron, for example, "falls" to the center of the differentiating body, its movement gives rise to friction that releases heat according to the formula: Energy E = - G M m / r where G is the gravitational constant, M and m are mass, and r is distance from the center. Thus, once the heat of accretion gets differentiation going, it causes a positive feedback with the heat of gravitational release, releasing more heat. C. Frictional Heating caused by denser core material sinking to the center of the planet. The descent of dense iron-rich material from the core to the center of the Earth creates heat. 2. Radiogenic Heat the heat given off when radioactive elements in the earth’s interior decay. A decisive role is played by the long-lived radioactive isotopes uranium-235 (235U), uranium238 (238U), potassium-40 (40K), and thorium-232 (232Th) in Earth’s mantle are the primary source of radioactivity. The amount of these elements in the earth is usually estimated according to the content of meteorites, based on the assumed similarity of the composition of meteorites to the composition of the earth’s mantle and core. 3. Tidal Friction one last ongoing source of planetary heat comes from tidal forces. We have discussed the nature of tides already, but not their effect on objects that experience them. In a nutshell: Whenever a tidal bulge is raised, frictional heat is generated. If a large bulge is being raised in solid material, considerable frictional heating results. MELC’s Describe what happens after magma(MELCS11ES-IIb-c-25) The rock materials deep within the earth’s crust is in molten state, and under great pressurefrom the weight above it. Throughout the earthquake belts there occur openings in a surfacelayers through which this melted rock is forced to the surface, forming a volcano. The movement of hot, liquid rock below and above the crust is called volcanism. A volcano is both the opening in the earth’s surface through which material erupt and the mountain built up by these materials. Magma, hot gases, and rock erupt from volcano Quiet eruptions form shield volcanoes; explosive eruptions form cinder cone volcanoes. Periods of quiet and explosive eruptions form composite volcanoes.  Intrusions are underground flows of magma that cool and harden into rock without ever having reached the surface.  The major types of intrusions are dikes, sills, laccoliths, batholiths, and stock. Volcano  If you could travel down a volcano, you would eventually reach a magma chamber. Heated magma rises up from magma chamber through cracks in solid rocks and it forces the cracks to widen.  In time magma breaks through the surface and erupts. Vent is the central opening of a volcano. Crater is cup-like depression that surrounds the vent. Atop some volcanoes is a large kind of crater called a caldera Volcanic Eruptions There are two basic kinds of eruptions: quiet and explosive.  Quiet eruption is when liquid lava flows out of a volcano’s vent. Thin, watery basaltic lava tends to flow quietly out of the vent. Explosive eruption is when lava is violently blown out of the volcano. Thick, pasty granitic lava containing much dissolved gas tends to erupt violently Volcanic Structures  Two factors which determine the shape a volcano: the type of eruption and the type of material erupted. A small, steep-sided, cone-shaped volcano made of volcanic cinders and other rock particles is called a cinder cone.  A shield volcano is a broad, dome-shaped volcano made by layers of solidified lava flows. Itis usually formed by quiet eruption.  Volcanic Structures  Composite volcano is a very large symmetrical cone of alternating layers of solidified lava and rock particles.  In some cases, magma is released as lava through a long open cracks. Basaltic lava may pour out of such cracks in huge quantities. These great lava flows pile up on top of one another and eventually form a flat Basalt plateau. Major Types of Intrusions  Sills form when magma intrudes between the rock layers, forming a horizontal or gently- dipping sheet of igneous rock.  Dikes form as magma pushes up towards the surface through cracks in the rock. Dikes are vertical or steeply-dipping sheets of igneous rock.  Batholiths are large, deep-seated intrusions (sometimes called Plutons) that form as thick, viscous magma which slowly make its way toward the surface, but seldom gets there.  Laccolith is a sheet-like intrusion that has been injected within or between layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward and folded, giving the laccolith a dome or mushroom-like form with agenerally planar base.