1) What is plate tectonics.2) Who thought of it, and why was he (correctly) disbelieved?3) New evidence, and then acceptance.

Synthesis- what is the main evidence for plate tectonics? Why was it believed in 1960 when it was not in 1930?

Next class: Mechanisms. The question about the volcanoes will have to wait until then.

What is a theory?

A theory is a systematically organized knowledge applicable in a relatively wide variety of circumstances…

It is not just a bunch of facts, but a general set of ideas that puts many facts into a coherent system.

Note fossil assemblagesNOTE WHERE FOSSILS START

Note well- this could be a map of depth as well..... Age=depth, close to land = deep!

What have we learned?

1) The ocean floor is young,2) It is created at mid ocean ridges, and moves away from them.3) It is oldest next to continents.

Next- Why?