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The Science of PHYSICAL GEOLOGY. “If your mind is empty, it is always ready for anything; it is open to everything.” Zen Proverb. The Science of Geology. Geology is the science that pursues an understanding of planet Earth
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The Science of PHYSICAL GEOLOGY “If your mind is empty, it is always ready for anything; it is open to everything.” Zen Proverb
The Science of Geology • Geology is the science that pursues an understanding of planet Earth • Physical Geology – Examines the materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface. • Historical Geology – Seeks an understanding of the origin of Earth and its development through time.
Why Study Geology? • Humans and the natural environment are interrelated. • Natural Hazards • Resources – Energy, Water, Agriculture, etc. • Environmental Issues • Understanding past geologic events will help us predict future geologic events.
Humans ask questions to understand the natural environment • How did the Universe and our Solar System form? • How did the Earth form? How do rocks form? • What is Plate Tectonics? • Why do earthquakes and volcanic eruptions occur? • What governs the location of mountain ranges? • Where do we get energy resources from? • How are gemstones formed? • Where do we get drinking water from? • What factors provide for the best agricultural areas? • What caused the ice ages? What causes global warming? Curiosity Leads to Exploration
Rocks and Fossils are important tools for geologists that tell a story of what Earth like in the past. • Life Forms (flora and fauna) • Plate Tectonics • Mountain Building • Volcanic Eruptions • Age Dating • Paleoclimate • Extinctions • Global Sea Level Rise and Fall • Ice Ages
How do geologists read the story recorded in the rock and fossil record?
Science operates through the use of the Scientific Method“A poverty of ideas is a more serious deficiency than faulty reasoning”Robert Magnan • Observe • Raise Question • Form Hypothesis • Test Hypothesis • Gather Data • Modify Hypothesis • Retest Hypothesis
Limits of Science • Questions (hypotheses) must be testable. • Results must be repeatable. • No moral or aesthetic judgments. • Can only test the natural, physical world. Scientific discoveries may be controversial… especially when they are first made.
What is a Hypothesis? • Hypothesis– A tentative (or untested) explanation. • A hypothesis that survives repeated testing and challenges, and is supported by a large body of evidence, may be elevated to the status of aTheory.
What is a Theory? • Theory – A well-tested and widely-accepted explanation of natural phenomenon that the scientific community agrees best explains certain observable facts. Examples of Theories: Theory of Relativity Plate Tectonics Theory Evolutionary Theory Atomic Theory Cell Theory
What is a Theory? • It is important to understand that the term “theory” has very different meanings to scientists and to the general public. • To a scientist, • A theory is not just a wild idea, a guess, or a belief. • It is based on objective facts. • Theories have survived close examination, and can be accepted with confidence. • A theory represents knowledge that has very high probability of being correct. • A theory remains open to tests and revision….that can make theories stronger/weaker. • Whereas, in common language, • “Theory” implies a lack of knowledge or a guess, conjecture, opinion, speculation. In this usage, a theory is not necessarily based on facts.
What is Scientific Law? • Paradigm– A theory may become a paradigm (a predominant worldview in the realm of human thought) or • Scientific Law after further testing and acceptance. • Example: Law ofGravity
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Summary of Scientific Method • Make observations: • The shape of Earth’s continents appear to fit together like pieces of a jigsaw puzzle. • Identify a question or problem: • At some time in the past, were the continents joined together forming one large land mass? • Develop working hypothesis (idea to explain the observations): • During Earth's history, the continents were joined together into one giant supercontinent (called Pangaea meaning "All Lands" in Greek).
Summary of Scientific Method • Determine ways totest the hypothesisby experimenting and eitheraccept, reject, ormodifythe hypothesis: • Develop tests that support or disprove that the continents were once joined. • Develop tests that support or disprove that the continents have moved (and may still be in motion). • The simplest explanation is typically the best. • What is some of the information we can use to do this? • Fit of Continents • Rock Types • Rock Structures • Fossils • Paleoclimate Data • Apparent Wandering of the Earth's Polar Regions • Geodetic evidence that continents are moving at a measurable rate
Summary of Scientific Method • Collect Data • Analyze Data: • Try to piece continents back together based on data collected • Interpret Data: • Are there trends or correlations? • Support or refute hypothesis and develop new hypothesis, if appropriate. • Repeat Steps 4 thru 10. • Only after repeated testing of the hypothesis, in which it gains considerable experimental or observational support, is it accepted and a theory is established. • A theory ultimately may become aparadigm or scientific law.