Continental Drift

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Continental Drift Noun

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[kon-ti-nen-tal drift]

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Continental Drift

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The theory that Earth's continents have moved over geologic time relative to each other, appearing to drift across oceans.

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Example: This map shows the supercontinent Pangaea, illustrating how Earth's continents were once joined together before they started to drift apart over millions of years.

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Hypothesis Noun

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[hy-poth-e-sis]

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Hypothesis

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A proposed explanation for an observation that can be tested through scientific study and experimentation to determine its validity.

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Example: This image shows how different soil types affect plant growth, illustrating a hypothesis about environmental factors.

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Pangaea Noun

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[pan-jee-uh]

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Pangaea

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The supercontinent that existed approximately 300 million years ago, incorporating almost all of the Earth's landmasses into one.

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Example: This image shows the ancient supercontinent Pangaea, illustrating how all of Earth's modern continents were once joined together in a single massive landmass.

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Supercontinent Noun

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[soo-per-kon-ti-nent]

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Supercontinent

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A very large landmass formed by the convergence and merging of multiple continents into a single, expansive continental plate.

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Example: This diagram shows the supercontinent Pangaea, a single giant landmass that existed millions of years ago, with modern continents labeled to show how they fit together.

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Gondwanaland Noun

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[gond-wah-nuh-land]

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Gondwanaland

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The large southern supercontinent that formed after the breakup of Pangaea, comprising most of today's Southern Hemisphere landmasses.

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Example: This map shows Earth around 150 million years ago, with the southern supercontinent 'Gondwanaland' clearly labeled before it broke apart into today's continents.

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Laurasia Noun

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[law-ray-zhuh]

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Laurasia

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The large northern supercontinent that formed after the breakup of Pangaea, comprising most of today's Northern Hemisphere landmasses.

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Example: This map shows the Earth 200 million years ago, when the supercontinent Pangaea had split into two large landmasses: Laurasia in the north.

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Fossil Noun

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[fos-il]

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Fossil

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The preserved remains, impression, or trace of a once-living organism from a past geological age, found within rock.

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Example: This diagram shows that older rock layers are found deeper in the ground and contain older, different fossils, which helps scientists determine the relative age of rocks.

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Glacier Noun

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[glay-sher]

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Glacier

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A large, persistent body of dense ice that moves slowly over land, carving the landscape and depositing rock debris.

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Example: This diagram illustrates how glaciers form in mountains and flow downwards, showing different types like valley glaciers and tidewater glaciers that reach the ocean.

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Plate Tectonics Noun

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[playt tek-ton-iks]

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Plate Tectonics

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The scientific theory that Earth's outer shell is divided into several large plates that glide over the mantle.

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Example: This diagram shows seafloor spreading, where magma rises at an oceanic ridge, creating new crust and pushing tectonic plates apart, causing continental drift.

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Lithosphere Noun

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[lith-o-sfeer]

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Lithosphere

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The rigid outer part of the Earth, consisting of the crust and upper mantle, which is broken into tectonic plates.

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Example: This diagram shows the lithosphere as the rigid outer layer of Earth, composed of the crust and upper mantle, which floats on the asthenosphere.