Geologic Time and Sun,Earth,Moon Systems

How many grams of Carbon-14 will remain after 17,100 years- C-14 has a half life 5,730 so 17,100 is about 3 half lives?

• 32 g

• 16 g

• 8 g

• 4 g

Answer explanation

After 17,100 years, which is 3 half-lives of Carbon-14 (5,730 years), the remaining amount is calculated as follows: 32g -> 16g -> 8g. Thus, 8 grams of Carbon-14 will remain.

Tags

NGSS.HS-PS1-8

What percentage of Rubidium-87 will remain after 4 half-lives?

• 25%

• 12.5%

• 6.25%

• 3.125%

Answer explanation

After 1 half-life, 50% remains. After 2 half-lives, 25% remains. After 3 half-lives, 12.5% remains. After 4 half-lives, 6.25% remains. Therefore, the correct answer is 6.25%.

Tags

NGSS.HS-PS1-8

Radiometric dating is possible because the rates of decay of radioactive isotopes _____.

• change over time

• change from place to place

• are constant

• vary widely

Answer explanation

Radiometric dating relies on the fact that the rates of decay of radioactive isotopes are constant over time. This consistency allows scientists to accurately date materials based on the remaining amounts of these isotopes.

Tags

NGSS.HS-PS1-8

How old is our solar system?

• 4.5 billion years

• 13.8 billion years

• 6,000 years

• 15,000 years

Answer explanation

Our solar system is approximately 4.5 billion years old, based on evidence from meteorites and the ages of the oldest rocks on Earth. The other options are incorrect as they do not reflect the scientific consensus.

Tags

NGSS.HS-ESS1-6

In radioactive decay, the​​ (a)   material is the original radioactive material, while the​ (b)   material is the what the material decays into.

• parent

• daughter

Answer explanation

In radioactive decay, the 'parent' material is the original radioactive substance, while the 'daughter' material is the product of its decay. Thus, 'parent' and 'daughter' are the correct terms to fill in the blanks.

Tags

NGSS.HS-PS1-8

How does carbon-14 enter the food chain and end up in living organisms?

• It is absorbed from the atmosphere by plants.

• It forms spontaneously in living organisms.

• It is inhaled by organisms and incorporated in their bodies.

• It forms inside living organisms from radioactive decay of heavier elements.

Answer explanation

Carbon-14 enters the food chain when plants absorb it from the atmosphere during photosynthesis. Animals then consume these plants, incorporating carbon-14 into their bodies, thus transferring it through the food chain.

Tags

NGSS.MS-LS2-3

Which set of characteristics produces a good index fossil?

• narrow time frame, wide geographic region

• wide time frame, narrow geographic region

• narrow time frame, narrow geographic region

Answer explanation

A good index fossil should have a narrow time frame to indicate a specific geological period and a wide geographic region to ensure it can be found in many locations, making it useful for correlating ages of rock layers.

Tags

NGSS.HS-LS4-1

Which letter best represents an index fossil?

• A

• B

• C

• D

Answer explanation

Index fossils are used to identify and date the layers of rock in which they are found. Choice C represents a species that existed for a short period but was widespread, making it an ideal index fossil.

Tags

NGSS.MS-LS4-1

What type of rock do fossils form in?

• Igneous

• Sedimentary

• Metamorphic

• Classic

Answer explanation

Fossils primarily form in sedimentary rocks, as these rocks are created from the accumulation of sediments that can trap and preserve organic materials over time. Igneous and metamorphic rocks do not typically contain fossils.

Tags

NGSS.MS-LS4-1

_{^{When scientists use logic to determine the age of one fossil compared to another, they use this type of dating.}}

• Relative

• Carbon

• Absolute

Answer explanation

Scientists use relative dating to determine the age of fossils by comparing their positions in layers of rock. This method helps establish which fossil is older or younger without providing an exact age.

Tags

NGSS.MS-ESS1-4