Name _____ ____________ ____________ ________________ _____ D ate _______ ____________ Period ____ _____
The Dating Worksheet Honors ScienceBelow are several problems based on radioactive decay. Yo ur job is to determine how old the rock/ fossils are base d on the
amounts of radioactive materials in their compositio n. Read the following problems and use the half-life of eac h element to help
you decide the age of each artifact. Carbon 14 ------ 5730 years Uranium 235 ---- 713 million years Potassium 40 ---- 1.3 billion years1. Scientists found a fossilized bone from an orga nism in a deep layer of rock. When they took the bone back to the lab they
realized that the bone had only 12.5% of the total Carbon 14 left. Based on the amount of Carbon 14 left in the bone how old is
2. In the picture below the igneous intrusion (V) was exami ned and scientists found that this rock had about 25% of the overall
Uranium 235 left in the composition of the rock. This fact helps scientists determine how old the intr usion is and in turn will give
clues about the age of the rock layers around an d beneath the intrusion. Using the amount of Uranium 235 left in the intrusion
how old is the intrusion? What are the relative ages o f the rock layers and fossils around and beneath the intr usion?
3. If a rock was determined to be around 3.9 billi on years old how much Potassium 40 would be left in that rock sample?
(Percentage of Potassium 40 )4. A radioactive material has a half-li fe of 30 days. You begin with 4 grams of radioactive material.
