Pieces of a Puzzle
Law Theory Tells you exactly what to expect in certain situations Newton’s Laws of Motion Theory An explanation that ties together many hypotheses and observations. It is based on scientific evidence.
Theory of Continental Drift ***add to comparing and contrasting foldable** Proposed by Alfred Wegener in 1915 He suggested that the continents were once joined together as one “supercontinent.”
The Theory of Plate Tectonics the Earth’s lithosphere is divided into tectonic plates that move around on top of the asthenosphere continents move at a rate of 2cm per year or about 1 inch year
Comparing the Theories (“Both” on the foldable) Continents move Earth was once made up of one large continent Same evidence proves the theories fossils puzzle pieces glacial deposits mountain ranges
Pangaea “all land” The name of the one supercontinent All continents joined together as one large land mass http://www.youtube.com/watch?v=q_IYQdKkWsU
What? – Theory of Plate Tectonics Alfred Wegener His studies were the 1st exhaustive research on the topic He compiled evidence from many disciplines His theory/hypothesis was not accepted by many scientists What? – Theory of Plate Tectonics It did not seem possible that the crust could move in that way Finally accepted with discovery of sea floor spreading in the 1960s
When? 245 mil yrs ago: Pangaea 180 mil yrs ago: Laurasia & Gondwana 65 mil yrs ago: continents continue to separate 1620: Alfred Bacon – puzzle 1858: Snider-Pellegrini - fossils 1910: Frank Taylor - geological 1915: Wegener – put it all together 1960: seafloor spreading
Where? continents and oceans lithosphere and asthenosphere
Evidence of Continental Drift Shapes of continents and the way they appear to fit together like pieces of a puzzle Similar rock structures found on different continents (highlight: locations of different types and ages of rock)
More Evidence of Continental Drift Fossils found on different continents (highlight: matching fossil remains) Glacial till deposits of same age and type found on different continents (highlight: glacial deposits) Matching mountain belts located on different continents (highlight: matching mountain belts)