1. Radiometric Dating Journal Entry #5 Continued

2. Radiometric Dating The process of determining the age of fossils by measuring the relative concentrations of radioactive isotopes in a sample.

3. Radiometric Dating The process of determining the age of fossils by measuring the relative concentrations of radioactive isotopes in a sample. Half-Life: The amount of time it takes for 1/2 of the radioactive isotopes in a sample to decay to the standard atomic weight

4. Examples http://www.colorado.edu/physics/2000/isotop es/radioactive_decay3.html http://www.colorado.edu/physics/2000/isotop es/radioactive_decay3.html

5. Radiometric Dating Types Carbon-14: Half-life of 5,730 years - useful for samples up to 70,000 years old

6. Radiometric Dating Types Carbon-14: Half-life of 5,730 years - useful for samples up to 70,000 years old Potassium-40: Half-life of 1.3 billion years - useful for samples older than 100,000 years

7. Radiometric Dating Types Carbon-14: Half-life of 5,730 years - useful for samples up to 70,000 years old Potassium-40: Half-life of 1.3 billion years - useful for samples older than 100,000 years Uranium-238: Half-life of 4.47 billion years - useful for samples older than 100,000 years