Geology204 The Fossil Record 9 30 am tues thurs The Nature Of Science January 29 2013 Information about the world around us is limited to our senses Science is the systematic acquisition and applications of knowledge about the structure and behavior of the physical universe gained via empirical evidence through observation measurement and experimentation Is a type of inquiry into nature characterized by the availability of empirically testable hypotheses Information about the world around us is limited to our senses which can be amplified by instruments World follows patterns and rules of observation Through repeated cycles of observation and testing and occasionally wholesale replacement of models we can more closely approximate the actual conditions of the world around us Science is based on arguments which involve stating ones case Empiricism evidence based on observation Observations data measurements P E A R L Physical Evidence And Reasoned Logic Humans see patterns in nature some real some false Method to sort between real and false patterns and to evaluate the relative support of different patterns The hypothetico Deductive Method Scientific Method Hypotheses formal statements of a pattern that appears to exist in a set of observations Scientific inquiry proceeds from the formulation of hypotheses based on previous observations and subsequent testing of these hypotheses from additional observations Scientific hypotheses MUST be falsifiable aka testable must be a NOT all hypotheses are falsifiable some are SUBJECTIVE and thus way in which you can test it not scientific Some testable in principle but cannot be tested at present because of limitations speculations all hypotheses are speculations until they are tested Hypotheses can be rejected but cannot be 100 proven Uncertainty is a part of science confidence intervals scale bars etc Provisionally accepted based on failure to disprove The more and more tests an hypothesis is subjected too the more its accepted Other things being equal choose the claim that is the simplest explanation for the phenomenon principles of Occams Razor other things being equal choose the claim that doesn t conflict with well established knowledge Principle of Consilience Proportion your acceptance of a claim to the amount of evidence for or against a claim Theory a model or a set of rules with broad explanatory power about some particular phenomenon a system of ideas intended to explain something a set of underlying rules operational logic or simply an explanation One can even use a good theory to predict How things would happen even if it is not likely to happen A theory doesn t have to be a good explanation it simply just needs to be an explanation it can be inaccurate and unrealistic SCIENTIFIC THEORY a comprehensive framework for describing explaining and making falsifiable predictions about related sets of phenomena based on rigorous observation experimentation and logic Test theories much like hypotheses parsimony consilience falsification Multiple Competing Theories Active research often revolves around multiple competing theories that currently explain the observations equally well The nature of the scientific endeavor then is to develop tests in which the different theories would predict different results Scientific explanations of why the item in question need not be a universal ongoing phenomenon such as the big bang origin of the solar system and planets origin of life origins of humans extinction of dinosaurs etc laws are scientific theories that can be rendered as mathematical equations tend to be useful for relatively simple phenomena but not for more complex ones Traditional laws may be rejected by same methods of testing as other theories January 31 2013 The truth so far as anything is held to be true in empirically tested studies true to the best of our knowledge Not all viewpoints are equally valid only valid when measured against observations of the natural world Eoanthropus Dawsoni Piltdown Man late 19th early 20th century continental human fossils but no british Big brain first in 1912 collector Charles Dawson found skull with apelike jaw and brain case of a human some suggested it was a chimera as 20th century progressed other early humans showed upright first big brain second seemed more likely for developmental path How do rocks form and how do they record environments of the past Systems set of interacting and interdependent entities that form an integrated whole Solar energy major driver giant nuclear fusion reactor solar energy comes from fusion in the sun s core Geothermal energy from radioactive decay in the earths core Gravitational energy Layers of the Deep Earth Knowledge from direct sampling and various types of sensors seismic magnetic gravitic etc Basic structure of Earth series of shells of differing composition temperature pressure and other physical properties Oceanic crust is thinner and denser Asthenosphere next lower part of mantle more mobile although still Lithosphere crust plus outer mantle rigid solid Plates slabs of lithosphere moving around on top of asthenosphere Evidence for moving continents Shared sets of animal and plant fossils with highly discordant distributions Matching mountain ranges geological formations across modern oceans Patterns of ancient glacial movement did not match modern climate zones these make sense if continents are united in single mass Continental drift Alfred Wegener German geophysicist and glaciologist in 1912 continents used to be joined together to form a super continent couldn t come up with a force that would enact this Continental drift seafloor spreading Seafloor spreading Plate tectonics plate velocities predicted by theory confirmed by GPS studies in the 1990 s Mantle convection cells drive the plates Plate Tectonics as plates move they interact with each other at their margins producing mountain building tectonics Rocks Naturally occurring cohesive solid comprised f one or more minerals or mineraloids Classified by their origin every rock is a record of the environment in which it was formed Three major types of rock Igneous Metamorphic Sedimentary All rocks are generated from previously existing rocks Melting and eruption Interaction of plates and or heat rising from the core mantle boundary melts into pre existing rock into magma Magma may cool and harden into rock before it reaches the surface Or it might reach the surface and erupt as lava and ash Igneous