This video is the final review in the Earth Science series, focusing on Unit 9: Geologic History. It covers three main topics: radioactive decay, relative dating, and the geologic time scale. The video explains the concept of half-lives and how to use the FAT chart for radioactive decay problems. It also discusses principles of relative dating, such as superposition and horizontality, and provides an overview of the geologic time scale, including eons, eras, and periods. The video concludes with practice questions to reinforce the concepts learned.

What is the half-life of Carbon-14?

• 1.3 billion years

• 5700 years

• 4.5 billion years

• 1.3 million years

Which isotope is used to date materials that were once alive recently?

• Rubidium-87

• Uranium-238

• Potassium-40

• Carbon-14

According to the principle of superposition, where is the oldest rock layer found?

• On the top

• In the middle

• On the bottom

• It varies

Tags

NGSS.MS-ESS1-4

What does the principle of horizontality state?

• All rock layers are deposited in vertical layers

• All rock layers are deposited in flat, horizontal layers

• All rock layers are deposited in tilted layers

• All rock layers are deposited in folded layers

What is an unconformity in geological terms?

• A layer that was deposited horizontally

• A layer that was deposited after erosion

• A layer that was deposited before erosion

• A layer that was never eroded

Which era is the oldest in the Phanerozoic eon?

• Cenozoic

• Precambrian

• Mesozoic

• Paleozoic

What is a mass extinction event?

• A period when new species evolve

• A period when a few species go extinct

• A period when many species go extinct

• A period when no species go extinct

Tags

NGSS.MS-LS4-1

What makes a good index fossil?

• Existed over a small area and for a long period

• Existed over a small area and for a short period

• Existed over a large area and for a long period

• Existed over a large area and for a short period

Why is volcanic ash considered a good time marker?

• It covers a small area and lasts a long time

• It covers a large area and lasts a short time

• It covers a small area and lasts a short time

• It covers a large area and lasts a long time

Which gas was added to the Earth's atmosphere approximately 2.2 billion years ago?

• Methane

• Carbon dioxide

• Nitrogen

• Oxygen