1 / 6

History of Life: Origins of Life

History of Life: Origins of Life. Chapter 14-3. Age of Earth. The earth is about 4.5 billion years old How did we measure that? Radiometric Dating = calculating the age of an object by measuring proportions of radioactive isotopes. Radiometric Dating.

garrison-santana
Download Presentation

History of Life: Origins of Life

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. History of Life:Origins of Life Chapter 14-3

  2. Age of Earth • The earth is about 4.5 billion years old • How did we measure that? • Radiometric Dating = calculating the age of an object by measuring proportions of radioactive isotopes

  3. Radiometric Dating • Radioactive Isotope = an unstable form of an element, decays into stable element, gives off energy (radiation) • Ex. Carbon-14 decays into Nitrogen • Ex. Potassium-40 decays into Argon-40

  4. Radiometric Dating • Half-life = the time it takes for half of a radioactive isotope to decay • Ex. K-40 half life is 1.3 billion years

  5. Practice • You are determining the age of an organic object using carbon-14 dating. You know that the half-life of carbon-14 is 5,730 years. If only 25% of the original amount of carbon-14 is left in the object, approximately how old is the object? Carbon-14 half life = 5,730 years When ½ is left then 5,730 years have gone by When ¼ is left then an additional 5,730 years have gone by Therefore the object is 11,460 (5,730 + 5,730) years old

  6. Your Turn To Try • You know that the half-life of K-40 is 1.3 billion years. If only 12.5% of the original amount of K-40 is left in the object, approximately how old is the object? • 3.9 billion years old • If the half-life of a radioactive isotope is 4,000 years, how much of the radioactive isotope in a specimen will be left after 12,000 years? • 1/8 or 12.5%

More Related