Dating Rocks

What two methods are used for determining the age of rocks and fossils?

• Relative and Absent Dating

• Absolute and Resolute Dating

• Relative and Absolute Dating

• Carbon and Water Dating

Tags

NGSS.HS-ESS1-5

Which fossil is relatively the oldest?

• Trilobite

• Ammonite

• Crinoid

• Gastropod

Tags

NGSS.HS-LS4-2

You find a rock sample with radioactive atoms present.  If 12.5% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)

• zero

• 1

• 2

• 3

Tags

NGSS.HS-PS1-8

You find a rock sample with radioactive atoms present.  If 25% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)

• zero

• 1

• 2

• 3

Tags

NGSS.HS-PS1-8

Why are isotopes with short half-lives not useful for dating very old rocks?

• because not enough of the parent isotope remains to measure accurately

• because not enough of the daughter product has formed to be detectable

• because neither the parent isotope nor the daughter product will be detectable

• because very old rocks would never have contained these isotopes

Tags

NGSS.HS-PS1-8

Which rock layer or intrusion is the youngest?

• A

• B

• C

• D

Tags

NGSS.MS-ESS1-4

A rock formed with 1000 atoms of a radioactive parent element, but only contains 250 radioactive parent atoms today. If the half-life of the parent element is one million years, how old is the rock?

• 250,000 years old

• 500,000 years old

• 1,000,000 years old

• 2,000,000 years old

Tags

NGSS.HS-PS1-8

If the  half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been ten half-lives?

• 10 years

• 100 years

• 1000 years

• 10000 years

Tags

NGSS.HS-PS1-8

The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____.

• the daughter product

• geologic time

• the half-life

• the half-time

Tags

NGSS.HS-PS1-8

Suppose you found a material in which 12.5% of the original radioactive atoms were still present.  If the half-life of an atom is 60 years, how old is the material?

• 30 years old

• 60 years old

• 120 years old

• 180 years old

Tags

NGSS.HS-PS1-8