Engage: Stories in the Soil

Phenomena: Scientists use soil horizons to uncover the clues to the mystery of a dead forest.

Time required: 15 minutes to show video and complete discussion.
Introduce the module with the following 6-minute PBS video clip: The Cascadia Subduction Zone. This clip shows scientists using "clues" found in the soil to uncover the mystery of a long-ago tsunami.

Play the clip and stop at the listed times to allow the students to record their answers to the questions below. (Optional: Provide a worksheet or template for the questions.)

1. Stop at 0:45 and ask the following:
   What is the mystery that the scientists are investigating?
   How does soil provide evidence and clues to solving their mystery?
2. Stop at 2:10 Ask: What is the evidence that they find in the soil?
3. Stop at 3:10 Ask: What is the claim that the scientists make?
4. Stop at 4:10 Ask: Describe the scientist's reasoning.
5. Show the remaining 2 minutes of the film and then talk more about sediment cores. Ask students to write out a summary paragraph – what is the "story in the soil?"
6. Replay the clip as needed and look at the clues and the characteristics of the soil.
7. Wrap up the discussion by asking students to share any other questions or observations that they may have made while watching this segment.