Activity 2: Haleakalā Detective Work
Materials & Setup
- A piece of light-colored string about a foot long
- Several colored markers
For each student
- Student Page “Haleakalā Detective Work” (pp. 17-24)
- Student Page “Haleakalā Detective Work: Questions About the Reading” (pp. 25-26)
- Student Page “The Dating Game: How Geologists Study the Age of Haleakalā Lava Flows” (pp. 27-31)
1) To begin a discussion about the reading, ask students to share their responses to each of the four questions from the Student Page “Haleakalā Detective Work: Questions About the Reading.”
2) Ask for student questions about the reading. Be sure to review how radiocarbon (carbon-14) dating works to be sure that students understand the process and how it is applied to dating lava flows. This is important background for the next part of this activity.
3) Hand out the Student Page “The Dating Game: How Geologists Study the Age of Haleakalā Lava Flows.” Have students read the student page, skimming through the table that compares dating techniques (p. 31) for now. (Students will also take this student page home to read more carefully as homework.)
4) Use the information in the reading as background for a discussion of the difference between absolute dating methods, such as radiometric techniques, which yield a numeric age for rocks, and comparative methods such as paleomagnetic dating.
5) To illustrate the results of using a comparative technique, follow the instructions on pp. 29-30 of the reading to perform a demonstration using string and colored markers. Ask students to discuss what additional information would be needed to assign a correct date to a lava flow using a comparative method (e.g., cross checking against dates established through absolute methods, using the rule of superposition).
6) As homework, have students read the Student Page “The Dating Game” more carefully. Assign one or more of the journal entries as written homework as well.
- Describe the difference between a dating method that yields an absolute age and one that is comparative. Illustrate the difference using examples of things that you know for certain (and how you know or learned them) and knowledge that you’ve needed to cross-check before feeling confident about it. These examples could be from everyday life.
- Using drawings and/or writing, illustrate the process of radioactive decay. Explain why it is important in determining the age of rocks.
- Describe the environmental conditions created by the geology of the summit area of Haleakalā. How do you think plants and animals would be adapted to live in this environment?
- Student Page “Haleakalā Detective Work: Questions About the Reading” (teacher version, pp. 15-16)
- Participation in class discussions
- Journal entries