Topic 4.1: What ideas, observations, and evidence led to the theory of plate tectonics?

Watch the following very informative, very accurate video https://www.youtube.com/watch?v=zocutif0cQY

Draw how you think the continents used to fit together

How did you arrive at your answer?

Did your drawing look something like this? https://www.youtube.com/watch?v=uGcDed4xVD4

The Continental Drift Hypothesis The world used to fit together like a jigsaw puzzle It was called Pangaea Pan means “all” Gaea means “world”

What evidence supported this hypothesis? The outline of the continents looked like they could fit together Geological information Ex. similar rocks/mountains found on different continents Fossil information Ex. Same species of fossil found on South America and Africa Climate information Coal found in Antarctica (made from decomposing living things)

So how do scientists know what’s under the surface? No tools can reach the inner layers of the earth Scientists use indirect evidence Measure energy waves during earthquakes Waves behave differently when they travel through different materials https://www.youtube.com/watch?v=eXiVGEEPQ6c

What are the layers of the Earth made of? Layer of the Earth Properties Crust Thin layer of solid rock Mantle Solid layer and soft, plastic like layer Outer Core Liquid Inner Core Solid

In what way does the structure of Earth support the idea that continents can move?

Studies of the ocean floor revealed where new rock was made. By using weighted ropes and later sonar, scientists learned that the ocean floor contained: Ocean ridges Underwater mountain ranges Trenches Deep, narrow areas in the sea floor

Ocean Crust Ocean rocks are much younger than land rocks because of seafloor spreading. Draw the diagram below in your notes.

Describe how the formation of new oceanic crust supports the idea that continents can move.

Theory of Plate Tectonics Earth’s surface is made up of huge slabs of rock called tectonic plates They float on a layer of fluid-like rock in the mantle 12 major plates and many smaller ones

Plate Tectonics Unifying theory that explains: Events that take place at/or below Earth’s surface How and why continents move How and why seafloor spreading occurs How, why and where earthquakes, volcanoes and formation of mountains occur https://www.youtube.com/watch?v=p-vNSqUy0l4 Pangea pop-up - https://www.youtube.com/watch?v=p-vNSqUy0l4