GLY1000
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- What is geology?
- "geo"=Earth and "ology"=discourse
- what are the two main disciplines of geology?
- physical geology & historical geology
- physical geography
- studies the materials composing the Earth and seeks to understand the processes that shape it
- historical geology
- studies the origin of the Earth & its development through time
- what was religion's influence on science?
- faith vs. observation & measurement
- Catastrophism
-
-at one time people believed that the Eather was shaped by great disasters according to Christian belief
-developed by analyzing historical records & genealogies found in Scripture
-17th & 18th centuries - uniformitarianism?
- the world processes are like a constant: the same physical, chemical, and biological laws that operate today operated in the past
- James Hutton
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-(1726-1797)
-uniformitarianist
-wrote "Theory of the Earth"
* * *-"the present is the key to the past" - Charles Lyell
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-(1830-1872)
-gave better explanation of uniformitarianism than James Hutton
-today we have to realize that processes have not always had the same relative importance or precisely the same rate
-suggested a much longer Earth history
-change tends to be relatively slow & cyclical! - how old is the Earth & how do we know?
-
- ~4.6Ga
-radiometric dating - hypothesis
-
a tentative [or untested] explanation constructed to explain natural phenomenon
-based on principles formulated by scientific "facts"
-always like to have multiple "working" hypotheses
-if it can't be tested, a hypothesis is not scientifically useful - theory
- a well-tested and widelt accepted view that the scientific community agrees best explains certain observable facts
- paradigm
-
theory that has been extensively documented, is held with a very high degree of confidence, and is comprehensive in scope
-e.g. plate techtonics - Aristotle's fish?
-
-people in ancient times found fossils & didn't know how to explain their origin or why they were in the Earth
-Aristotle hypothesized that there were fish that lived inside the Earth like in the sea, they were just frozen and that's why they appeared as skeletons - doppler effect
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Heard an ambulance go by recently? Remember how the siren's pitch changed as the vehicle raced towards, then away from you? First the pitch became higher, then lower. Originally discovered by the Austrian mathematician and physicist, Christian Doppler (1803-53), this change in pitch results from a shift in the frequency of the sound waves,
-As the ambulance approaches, the sound waves from its siren are compressed towards the observer. The intervals between waves diminish, which translates into an increase in frequency or pitch. As the ambulance recedes, the sound waves are stretched relative to the observer, causing the siren's pitch to decrease. By the change in pitch of the siren, you can determine if the ambulance is coming nearer or speeding away.