15.14: Understanding Earth's History- Challenge 3

1. The distinctive patterns of tree rings, ice cores, and ___ can be used to determine the time they were formed.

varves

2. The counting of ___ layers is one of the methods of ice core dating.

dust-snow

3. ___ analysis yields clues about how changes in the concentration of atmospheric gases have influenced Earth's climate over time.

Ice core

4. If two half-lives have passed, ___ percent of the parent isotope remains.

25

5. Radioactive decay of an isotope leads to the formation of a ___ product.

stable daughter

6. ___ discovered the spontaneous emission of particles that they called "radioactivity."

Pierre and Marie Curie

7. When an organism dies, carbon-14 decays to stable nitrogen-14 by releasing a ___.

beta particle

8. Carbon dating measures when an organism died because only then does ___.

carbon-14 decay into nitrogen-14

9. Carbon-14 dating is used for dating human remains and artifacts because ___.

carbon-14 has a relatively short half-life and early human fossils and materials often contain carbon

10. ___ is the most useful technique for dating Earth's matter and coming up with a quantitative age for the planet.

Radiometric dating

11. ___ determines the age of an object based on the concentration of a particular radioactive isotope contained within the object.

Radiometric dating

12. Earth is ___ years old.

4.6 billion