25 Jun 2011

Geochronology: radiocarbon dating

In-Class Activity

Submitted by mike knapp, UMASS
Categories
Description: 

This is written for a freshman seminar course, "Nuclear Chemistry and Medicine," open to all majors.  It meets once per week for one hour, and is meant to facilitate the transition into college for first-year students by providing an informal educational experience. It should be adaptable to a lecture-format course, and I will try to do this for my Junior-year Inorganic Chemistry. 

"The topics will range from the basics of nuclear reactions to the social ramifications of nuclear chemistry. While nuclear chemistry has many beneficial uses, including for medicine and power, even these include an environmental price. Come learn how to use nuclear decay for biochemical research, how nuclear fission gets used to produce power, and discuss the costs/benefits of these uses." 

Broader goals of the seminar are: active student learning, meet a faculty member in an informal setting, and connect with other students as a community. 

In order to facilitate participation, I break down the daily topic into smaller parts, and make student groups responsible for that part. Each class meeting will consist of a mix of brief student presentations and discussion.  Break students into groups of 3-4 students.Assign one sub-topic to each student group; each group presents to the class for ~10 minutes.

AttachmentSize
Microsoft Office document icon radiocarbonQ.doc28.5 KB
Learning Goals: 

• Contrast exponential decay with linear decay graphically

• Use exponential decay to date the age of materials based on 14C decay

• Identify appropriate radioisotope for dating based on material/age

• Synthesize/integrate data from multiple sources by comparing the radiocarbon age to archaeological age

• Apply mass balance to nuclear reactions (upper-level)

Equipment needs: 

Computer with presentation equipment and a display screen.

Students will need access to a calculator with a LOG function

Related activities: 
Implementation Notes: 

Assign one task to each student group; each group presents for ~10 minutes.

1) First-order kinetics: exponential decay and half-life. 

2) Radiocarbon dating

 

3) Dating of specific organic material using C-14: Otzi, the iceman

More advanced classes may expand to include K/Ar dating for mineral, or discussion of atmospheric C14 origin

The challenge will be to ensure that the students use resources aside from "Wikipedia."

Time Required: 
about 1 hour
Evaluation
Evaluation Methods: 

Peer and faculty assessment. Each student answers a two-part question: How did your contributions influence learning for the class? How did the contributions of another student influence your learning?

Take home quiz: calculate the date of a specific object based on the C-14 data.

Creative Commons License: 
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