Earth's History

Science

Watch Lesson: Earth's History

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The Hypothesis That All The Continents Are Moving Very Slowly Across Earth’s Surface.

Continental Drift

Continental Drift Simple Definition

A Timeline Of Earth's History Based On Major Changes.

Geologic Time Scale

Geologic Time Scale Simple Definition

The Time It Takes For Half The Atoms Of A Radioactive Isotope To Decay.

Half-life

Half-life Simple Definition

A Fossil From An Organism That Existed For A Short Time, It Is Used To Determine The Age Of Other Fossils.

Index Fossil

Index Fossil Simple Definition

The Oldest Rock Layers Are At The Bottom And Youngest Are At The Top.

Law Of Superposition

Law Of Superposition Simple Definition

The Theory That Earth's Crust Is Made Of Moving Plates.

Plate Tectonics

Plate Tectonics Simple Definition

The Breakdown Of An Unstable Atomic Nucleus, This Releases Particles And Energy.

Radioactive Decay

Radioactive Decay Simple Definition

The Age Of One Object Or Event Compared To Another.

Relative Age

Relative Age Simple Definition

A Method Of Comparing Fossils Or Rocks To Determine Which Is Older.

Relative Dating

Relative Dating Simple Definition

A Rock That Forms When Sediment Is Pressed And Cemented Together.

Sedimentary Rock

Sedimentary Rock Simple Definition

A Fossil Formed In Soft Sedimentary Rock, Like A Footprint.

Trace Fossil

Trace Fossil Simple Definition

The Theory That Geologic Processes Are The Same Today As They Were In The Past.

Uniformitarianism

Uniformitarianism Simple Definition