Age of the Earth

High school (ages 12+)
Environment & Earth

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/age-of-the-earth

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the key isotopic systems used?Uranium-Lead (U-Pb), Potassium-Argon (K-Ar), Rubidium-Strontium (Rb-Sr), Samarium-Neodymium (Sm-Nd)
2. What is the oldest terrestrial minerals?Zircons dating to approximately 4.4 billion years
3. How old is Earth?Earth is about 4.54 billion years old, which is the time since it formed from the solar system.
4. How do scientists figure out Earth's age?They use radiometric dating, measuring how long radioactive atoms in rocks have changed into stable atoms. By comparing the amounts of parent and daughter atoms, they calculate the time since the rock formed.

Geochronology: The scientific study of the age of rocks and geological events.
Isotope: Atoms of the same element with different numbers of neutrons, some of which are radioactive.
Half-life: The time it takes for half of a radioactive isotope in a sample to decay into a daughter isotope.
Planetary Differentiation: The process by which a planet separates into layers based on density during its formation.