Science Starter: THUR WEEK 5 Last night there was an 8.3 magnitude earthquake that struck in Illapel, Chile South America. What was the most likely cause of this earthquake? A. the movement of the Nazca Plate and S. American plate along a transform boundary B. the subduction of the Nazca Plate under the S. American Plate C. The spreading of the Nazca Plate from the S. American Plate D. The subduction of the S. American Plate under the Nazca Plate

ESSAY QUESTION At their highest point , nearly 320 million years ago, the Appalachian mountains were higher than Mt. Everest. Today, Mt. Everest is about 23,000 ft. higher than the Appalachians and is still growing. Both mountain ranges were formed by the collision of two tectonic plates. Explain two reasons why the Appalachians are getting smaller.

Inside the Earth What does the inside of Earth look like? Layers How are the layers arranged? By density What happens to the temperature and pressure as you travel into the center of Earth? Both Increase

Inside the Earth How do we know so much about Earth’s Interior? Seismic waves from earthquakes Seismic waves travel at different speeds and directions as they pass through the different layers of Earth.

Restless Continents True or False: The continents are always moving? What is this called? Continental drift Who created the theory of continental drift? Alfred Wegener

Restless Continents What discovery helped prove Wegener’s theory? Mid-ocean ridges How did we discover mid-ocean ridges? Better Technology/sonar

Restless Continents What process happens at mid-ocean ridges to help move Earth’s plates? Sea-floor Spreading

What is the proof of sea-floor spreading? 1. Age of the sea-floor The sea-floor is older as you move farther from a mid-ocean ridge 2. Magnetic stripes on the sea-floor

The Theory of Plate Tectonics The theory that Earth’s lithosphere are divided into _______ that move around on top of the ______. Plates, asthenosphere

The Theory of Plate Tectonics What is the main cause of plate movement? Convection currents How do convection currents work? Core heats up molten rock making it less dense. The molten rock rises up towards the crust, where it cools down. As it cools it gets more dense and begins to sink back down through the mantle. This cycle will repeat over time, gradually moving Earth’s plates. Flash Presentation

The Theory of Plate Tectonics Two plates moving away from each other = ______ Divergent boundary Two oceanic plates are spreading apart =________ Mid-ocean Ridge/Sea-floor spreading Two continental plates diverging =________ Rift Valley

The Theory of Plate Tectonics Two plates colliding with each other = _______ Convergent Boundary Two continental plates colliding = ________ Mountains Oceanic plate and Continental plate colliding=_____ Trenches, mountains, and volcanoes

The Theory of Plate Tectonics At convergent boundary between a continental plate and an oceanic plate what process will happen? Subduction Why? The oceanic plate is more dense, so it goes under the continental plate.

The Theory of Plate Tectonics What type of boundary forms when two plates slip or slide past each other? Transform Boundary What disaster can be associated with transform boundaries? Earthquakes