Absolute vs. Relative Dating

Front

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

Back

because not enough of the parent isotope remains to measure accurately

Front

Scientists use radioactive decay to measure...

Back

absolute time

Front

The length of time required for half of the radioactive atoms in a sample to decay is its...

Back

half-life

Front

How does absolute age differ from relative age?

Back

only absolute dating finds the age in years

Front

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

Back

are constant

Front

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

Back

the half-life

Front

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

Back

200 years

Front

According to the law of superposition, where are the oldest fossils found?

Back

Near the bottom of the rock layers

Front

Which rock layer in the diagram seems to be the oldest?

Back

A

Front

According to the law of superposition, which layer is the youngest?

Back

A