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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 Earth’s 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 Earth’s 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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This note was uploaded on 03/05/2011 for the course GEOL 101 taught by Professor All during the Fall '08 term at George Mason.
- Fall '08