How are radioactive isotopes used to determine the absolute age of igneous rock?

1 Answer
Write your answer here...
Start with a one sentence answer
Then teach the underlying concepts
Don't copy without citing sources
preview
?

Answer

Write a one sentence answer...

Answer:

Explanation

Explain in detail...

Explanation:

I want someone to double check my answer

Describe your changes (optional) 200

4
Mar 31, 2016

Answer:

When the isotopes decay, scientists can find out how old the rock is depending on the radioactive isotope's half-life.

Explanation:

Radioactive isotopes are unstable and will decay. For example, when humans die carbon-14 decays. The isotopes will decay into a stable isotope over time. Scientists can tell how old the rock was from looking at the radioactive isotope's half-life, which tells them how long it would take for there to be half the radioactive isotope and half the stable isotope. At the next half-life there will be 25% of the radioactive isotope and 75% of the stable isotope. At the next half life there will be 12.5% radioactive and 87.5% stable.

Example:

Carbon-14 is a radioactive isotope with a half life of 5,730 years. How old would carbon-14 be when there is 75% carbon-14 in the rock?

75% is half of the time before the half-life, so it would be 2,365 years.

Hope this helps. Half life helps scientists find how much the isotope has decayed and the age of the rock.

Was this helpful? Let the contributor know!
1500
Trending questions
Impact of this question
2230 views around the world
You can reuse this answer
Creative Commons License