Radioactive Dating Game Lab

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EASC 205 Radioactive Dating Game Lab (due 2.29.20)

Purpose: Students will use the radioactive decay rate and original-daughter element ratios of Carbon-14

and Uranium-238 to determine the ages of different objects.

Materials: Computer with Radioactive Dating Game. Can use web site:

http://phet.colorado.edu/simulations/sims.php?sim=Radioactive_Dating_Game

Procedure:

1. Start computer and go to internet. Find web site. 2. Click on tab for Decay Rates. Check Carbon-14. 3. The half-life for Carbon-14 is _________ years. 4. The half-life for Uranium-238 is ______________ years. 5. Place 1000 C-14 atoms onto screen. Start decay.

a. Stop decay at one half-life. How many Carbon-14 atoms remain? _______ b. After 2 half-lives, how many Carbon-14 atoms remain? ________ c. After 3 half-lives, how many Carbon-14 atoms remain? ________

6. Click on tab for Dating Game. Start measurements with living and dead objects on or just under the surface of the Earth. With these objects use Carbon-14 for measurements. Record guesses

and measured ages. Ancient fossils will have no Carbon-14. You must use the ages of rocks

(from Uranium-238) in the same rock layer as the fossils to determine the fossil’s age.

7. Switch to Uranium-238. Now make guesses and measure the ages of the rocks. Record answers.

Data: Radiometric Ages for Various Objects

Object Carbon-14 Uranium-238 % of Original Guessed Age Measured Age

Animal Skull

Living Tree

Distant Living

Tree

House

Dead Tree

Bone

Wooden Cup

1 st human skull

2 nd

human skull

Fish Bones

Fish Fossil 1

Rock 1

Dinosaur Skull

Rock 2

Trilobite

Rock 3

Rock 4

Rock 5

Conclusion: Write out a technical lab report as depicted on Syllabus and should capture among other

details: “What you did; a summary of your results; and, what you learned.”