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Absolute vs Relative Dating

Page history last edited by coylem@... 8 years, 4 months ago

Essential Questions:

  1. How do geologists determine the age of rocks or other unknown objects found on earth?
  2. How do we know that the earth is 4.6 billion years old?
  3. What is the difference between absolute and relative? 


Enduring Understandings


  1. Relative dating is a qualitative measurement and does not give an exact age of an object, it is sometimes based on the geological concept of superposition.
  2. The geological law of superposition tells us that old "things" are buried deeper in earth's crust than new "things."
  3. Absolute dating is a quantitative measurement and it is based on the natural radioactivity of elements contained in rocks and fossils.
  4. Absolute dating is based on comparing the ratio of a naturally occurring radioactive isotope and its decay products, using a known decay rate called "half-life."


Textbook Connection:

  • Relative Dating read Chapter 17.1 in Modern Earth Science
  • Absolute (Radiometeric) Dating read Chapter 17.2 in Modern Earth Science
  • The Chemistry of the Earth Chapter 8.1 and Chapter 8.2 


The Basic Principles of Geology (also a book by Charles Lyell)

  1. Principle of Original Horizontality
  2. Law of Superposition
  3. Principle of Lateral Continuity
  4. Principle of Cross-cutting
  5. Principle of Faunal Succession




GeoSleuth (In Class "Murder" Mystery Lesson) Powerpoint Presentation

Introduction to Geology: 

Chemistry Review:


Radioactive Decay Notes: *Honors classes only


Half-life Practice Problems:









Relative Dating Class Activity

 Relative Dating Activity.doc  (cards below go with this activity)

Relative Dating Cards Part 1.doc

Relative Dating Cards Part 2.doc


At what rate do atoms change in radioactive decay?  (Class Penny Lab)

 Radiometric Dating Half Life Lab.pdf


 Virtual (online) Radiometric Dating Lab


Simple Demo of Radioactive Decay


Radiation as a Cancer Treatment


Absolute Dating Activity:

Frosty the Snowman Lab, applying what you learned about radiometric dating to a crime 

Frosty the Snowman Radiometric Dating.doc



RadiometricDatingWS.pdf  (ignore the second page)


Using Radiometric Dating in Geology


Where Does All of Earth's Heat Come From?



A little off topic.. Have you ever heard of Schrodinger's Cat?  




...if you were thinking, "That radioactive material must have undergone beta decay since it was emitting an electron, then, well, you're very observant!"

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