Earth Science Module 1 PDF

Earth Science Module 1: The Nature of Earth Science Raymund B. Bolalin DLSU Physics Department Module 1: Learning Outcomes The learners should demonstrate an understanding of: the sciences that collectively makeup Earth science; and the subsystems that make the Earth. Module 1:...

Earth Science Module 1: The Nature of Earth Science Raymund B. Bolalin DLSU Physics Department Module 1: Learning Outcomes The learners should demonstrate an understanding of: the sciences that collectively makeup Earth science; and the subsystems that make the Earth. Module 1: Objectives After this module, the learners should be able to: list and describe the sciences that collectively make up Earth science. describe the characteristics of Earth that are necessary to support life; and explain that the Earth consists of four subsystems, across whose boundaries, matter, and energy flow. Earth Science All sciences that seek to understand Earth Understanding of Earth’s neighbors in space Earth Science Earth Science is the study of our planet, its changing systems, and its position in the Universe. Earth Science Earth Science includes – Geology – literally the “study of Earth” – Oceanography – a study of the ocean – Meteorology – the study of the atmosphere and the processes that produce weather – Astronomy – the study of the universe Earth Science Earth Science investigates and tries to answer questions like: I. Why do we have seasons? II. How can we predict the weather? III. Why are stars grouped and move together in the night sky? IV. What forms a landscape? Earth Science is Environmental Science Natural hazards Resources People Influence Earth processes Why is earth science important? ❑Forecast potential disasters and help save lives and property. ❑Gain access to the Earth’s resources. ❑Protect the environment. Earth Science: Scales of Space and Time Geologic Time – Span of time since Earth’s formation – Earth is 4.6 billion years old – Concept of “recent” is different Geologic Time Scale – Divides history of Earth into different units Magnitude of Geologic Time Scientific Inquiry Science assumes the natural world is – Consistent – Predictable Goal of science – To discover patterns in nature – To use the knowledge to predict Scientific Inquiry An idea can become a – Hypothesis (tentative or untested explanation) – Theory (tested and confirmed hypothesis) – Paradigm (a theory that explains a large number of interrelated aspects of the natural world) Scientific method – Gather facts through observation – Formulate hypotheses and theories Observation and Measurement Scientific Inquiry Scientific knowledge is gained through – Following systematic steps Collecting facts Developing a hypothesis Conduct experiments Reexamine the hypothesis and accept, modify, or reject – Theories that withstand examination – Totally unexpected occurrences Early Evolution of Earth Origin of Earth – Most researchers believe that Earth and the other planets formed at essentially the same time Nebular theory – Solar system evolved from an enormous rotating cloud called the solar nebula – Nebula was composed mostly of hydrogen and helium Early Evolution of Earth Nebular theory continued – About 5 billion years ago the nebula began to contract – Assumes a flat, disk shape with the protosun (pre-Sun) at the center – Inner planets begin to form from metallic and rocky clumps – Larger outer planets began forming from fragments with a high percentage of ices The Nebular Theory Early Evolution of Earth Formation of Earth’s layered structure – As Earth formed, the decay of radioactive elements and heat from high-velocity impacts caused the temperature to increase Iron and nickel began to melt and sink toward the center Lighter rocky components floated outward, toward the surface – Gaseous material escaped from Earth’s interior to produce the primitive atmosphere Earth’s Spheres Hydrosphere – Ocean – the most prominent feature of the hydrosphere Nearly 71 percent of Earth’s surface About 97 percent of Earth’s water – Also includes fresh water found in streams, lakes, and glaciers, as well as that found underground Hydrosphere Earth’s Spheres Atmosphere – Thin, tenuous blanket of air – One half lies below 5.6 kilometers (3.5 miles) Earth’s Spheres Biosphere – Includes all life – Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere Earth’s Spheres Geosphere – Solid Earth – Extends from surface to the center of the planet – Largest of Earth’s four spheres Geosphere Solid Earth – Based on compositional differences, it consists of the crust, mantle, and core – Divisions of the outer portion are based on how materials behave Earth’s Layered Structure Geosphere Crust – Earth’s relatively thin, rocky outer skin – Continental crust Less dense, many rock types Granitic – Oceanic crust Dense, basaltic rock Geosphere Mantle – Solid, rocky shell – More than 82 percent of Earth’s volume – Upper mantle Lithosphere – entire crust and uppermost mantle Asthenosphere – relatively soft layer – Lower mantle Very hot, strengthens with depth Geosphere Core – Iron-nickel alloy – Outer core Liquid layer Earth’s magnetic field – Inner core Solid The Mobile Geosphere Plate tectonics – Earth’s lithosphere is broken into slabs (lithospheric plates) that are in continuous motion. Earth’s Major Lithospheric Plates Plate Motion Plates move very slowly Three types of plate boundaries – Divergent – plates pull apart – Convergent – plates move together – Transform fault – plates slide past each other Convergent and Divergent Boundaries The Face of Earth Continents – Flat features that average 0.8 km (0.5 mi) in elevation – Granitic rocks Ocean basins – Average 3.8 km (2.8 mi) below sea level – Basalitic rocks Major Features of Continents Mountain Belts – Principally the circum-Pacific belt and the Alps/Himalayas Stable Interior – Shields – expansive, flat regions of deformed crystalline rock – Stable platforms – deformed rocks covered by sedimentary rocks. The Continents Major Features of Ocean Basins Continental Margins – Portions of seafloor adjacent to major landmasses – Includes: Continental shelf – gently sloping platform extending seaward from shore Continental slope – steep drop off at edge of continental shelf Continental rise – more gradual incline; continental slope merges with thick accumulation of sediments Major Features of Ocean Basins Deep-Ocean Basins – Between continental margins and oceanic ridges – Abyssal plains – flat features of deep-ocean basins – Deep-ocean trenches – deep depressions in ocean floor – Seamounts – submerged volcanic structures Major Features of Ocean Basins Oceanic Ridge – Also called mid-ocean ridge – Includes Mid-Atlantic Ridge and East Pacific Rise – Continuous mountain belt that winds around globe – Many layers of igneous rock Earth as a System Earth is a dynamic body with many separate but highly interacting parts or spheres Earth system science studies Earth as a system composed of numerous parts, or subsystems System – any size group of interacting parts that form a complex whole Earth as a System System – Closed systems are self-contained (e.g., an automobile cooling system) – Open systems – both energy and matter flow into and out of the system (e.g., a river system) Earth System Science Earth as a system – Consists of a nearly endless array of subsystems (e.g., hydrologic cycle, rock cycle) Earth System Science Earth as a system – Sources of energy Sun – drives external processes such as weather, ocean circulation, and erosional processes Earth’s interior – drives internal processes including volcanoes, earthquakes, and mountain building – Humans are part of the Earth system