Earth HistoryLesson 1: What’s Inside the Earth

Inner Core:The innermost layer of the earth, an extremely hot, solid sphere of mostly iron and nickel. The inner core is 3,200 to 3,960 miles (5,150 to 6,378 km) below the surface and about 750 miles (1,200 km) thick.

Outer Core:This layer of the earth lies between the mantle and the solid inner core. It is the only liquid layer, a sea of mostly iron and nickel about 1,400 miles (2,300 km) thick.

Mantle:This dense layer of the earth is made of hot, semisolid rock and is located directly below the crust. It is about 1,800 miles (2,900 km) thick.

Crust:Hard and rigid, the earth's outermost and thinnest layer. It is only a few miles (5 km) thick under the oceans and averages 20 miles (30 km) thick under the continents.

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Key Vocabulary:

Oceanic Crust:The type of crust lying under the oceans of the world. It is only 4 to 6 miles (7 to 10 km) thick and usually younger than continental crust.

Boundary: The border between two tectonic plates.

Continental crust:A layer of the earth's crust that lies under the seven continents. It is about 20 to 40 miles (35 to 70 km) thick and very old

Lithosphere:Made up of the crust and a tiny bit of the upper mantle, this zone is divided into several constantly (very slowly) moving plates of solid rock that hold the continents and oceans.

Asthenosphere:A hot, malleable semiliquid zone in the upper mantle, directly underneath the lithosphere, on which the plates of the lithosphere move (or float).

Tectonic Plates:Several large slabs of the lithosphere that hold the continents and oceans and are slowly but constantly moving around the earth.

Convergent boundary:The boundary that occurs where two plates are pushing toward each other.

Divergent boundary:The boundary that occurs where two plates are moving apart from each other.

Transform boundary:The boundary that occurs where two plates slide past each other.

Introduction What’s Inside Earth

Task:• Click on the above image to open interactive website.• Read the Introduction• Use the glossary and the chapters to define each vocabulary word.• Go to next slide

What’s Inside The Earth?

Task:• Inside your science note, illustrate the different layers of the Earth . Be sure

your notes are detailed. Use the link below for additional information.• Link: Earth’s Interior• When complete, go to next slide.

Tectonic PlatesWho was Alfred Wegener?A German scientist from the early 1900’s

What was Alfred Wegener’s view of the continents?Alfred Wegener noticed that the coastlines of Africa and South America looked like they might fit together. He also discovered evidence that the same plant and animal fossils were found along the coasts of these continents, although they were now separated by vast oceans. In addition, he noticed that geologic formations, like mountain ranges, on the two continents also matched up

What was Pangaea?Wegener suggested that the earth's continents were once joined together in one large mass. He called the original landmass (or supercontinent) "Pangaea," the Greek word for "all the earth." According to Wegener, over time "Pangaea" split apart and the different landmasses, or continents, drifted to their current locations on the globe.

Pangaea begins to break up and splits into two major landmasses — Laurasia in the north, made up of North America and Eurasia, and Gondwana in the south, made up of the other continents.

Gondwana splinters further — the South America-Africa landmass separates from the Antarctica-Australia landmass.

The Indian landmass breaks away from the Antarctica-Australia landmass.

Major rifting of Laurasia, with the North American landmass separating from Eurasia.

South America and Madagascar separate from Africa.

Greenland separates from North America.

Australia separates from Antarctica and moves north.

The Indian landmass collides with Asia.

Click the link above. In the instruction box you will see directions printed in red. Read over carefully and then click “Begin” After you have the correct order of the continents, answer the bonus question.

When you have completed the question, return to this presentation and go to the next slide.

Continents Over Time

Plate Boundaries

Using the map above, identify each of the plates on the Plates and Boundaries Handout.

What is the difference between continental crust and oceanic crust?

Completely copy the table below in your science notebook. Use the information from the Plate Boundaries Chapter to complete the table. Be sure you have a clear understanding of the 3 different boundaries as well as some examples. When you have completed the table go to next slide.

Carefully study the map you filled in of the plate locations below, click the map and play Plate Boundaries Challenge

End of lesson