Table of Contents. Titles: Age and Time Page #: 13 Date: 9/12/12. Objective. Students will be able to describe the method that scientists use to date the age of the earth. Students will be able to define the half life of a molecule. Words of the Day.
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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Earth is between 4.5 and 4.6 Billion years old.
Early scientists had dated Earth from being ~ 4000 years old to 1.64 Billion years old.
They were WRONG! Very Wrong.
Radiometric Dating - This is the technique that modern scientists use to estimate the age of the earth.
This technique uses the radioactive nature of rocks to calculate their age.
Radiometric Dating uses the radioactive nature of rocks to calculate their age.
Some rocks contain isotopes - molecules with unstable nuclei, that give off particles at a constant rate (radioactive decay.)
An isotope has 7 particles in its nucleus on day 1.
On day 2 the isotope only has 6 particles.
On day 3 the isotope only has 5 particles.
As particles leave the “parent element” it changes into a “daughter product.”
Half Life: The time over which 1/2 of the atoms of a radioactive isotope decay
Examples: The half life of Carbon-14 is 5730 years.
The half life of Uranium-235 is 740 Million years.
The half life of Potassium-40 is 1.3 Billion years.
Earth is believed to be between 4.5 and 4.6 Billion years old based on isotopes found in meteorites and in lead minerals in rocks.
3 and 1/2 particles