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Unformatted text preview: Exam 1 Earth Materials Exam September 30 Introduction Physical Geology investigates the materials of the earth and seeks to understand many processes Relationships o Natural hazards o Natural resources o Environmental issues Geologic time o Involves vast times: millions of years o An appreciation for the magnitude of geologic time is important because many processes are very gradual Nature of scientific inquiry o Science assumes the natural world is consistent and predictable o Goal of science is to discover patterns in nature and use knowledge to make predictions o Scientists collect data through observation and measurements Scientific Method o Gathering facts through observations o Formulation of hypotheses and theories o Hypothesis a tentative, or untested, explanation o Theory a well-tested and widely accepted view that the scientific community aggress best explains certain observable facts Earth System Earth is a system of 4 interconnected systems o Hydrosphere o Atmosphere o Biosphere o Solid earth Earth is a system powered by the sun that drives external processes on the earths surface The earth is also powered by the Earths interior Nebular Hypothesis - Origin of planet Earth The earth and the other bodies of the solar system formed from collapsing interstellar material Layered structure developed by chemical segregation early in the formation of earth Dynamic Earth the theory of plate tectonics A comprehensive model of Earths internal workings Minerals Mineral building blocks of rocks o Naturally occurring o Inorganic solid o Organized molecular structure o Rock a solid aggregate or mass of minerals o Gemstone exotic coloration of some minerals o Nearly 4,000 minerals have been named Chemistry o Chemical bonding formation of a compound by combining two or more elements o Ionic bonding atoms gain or lsoe outermost (valence) electrons to form ions o Covalent bonding atoms share electrons to achieve electrical neutrality, compounds are stronger than ionic bonds o Metallic bonding electrons migrate freely among atoms, good conductors of electricity, weaker and less common than ionic or covalent bonds o Isotopes an atom that exhibits variation in its mass number o Radioactive decay some isotopes that have an unstable nuclei that emit particles and radioactive energy Structure of Minerals o Structure an orderly array of atoms chemically bonded to form a particular crystalline structure o Mineral polymorphs minerals can have the same chemical composition but have different crystalline structures Graphite and Diamond have the same chemical formula but appear different as a result of having different structures Physical Properties o Crystal form evidence of the orderly internal arrangement of atoms o Luster appearance of a mineral in reflected light Metallic, non metallic o Color Sometimes a same minerals can have a variety of colors...
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- Fall '08