Collapse 2: Interpreting the Evidence

What You Need


If you choose to have students do the Garbage-ology activity in class, you’ll need:

  • 1-2 bags of garbage per group of students
  • Drop cloths
  • Rubber gloves for all participants
  • Additional garbage bags
Collapse 2: Interpreting the Evidence Roberrific at en.wikipedia [GFDL or CC-BY-SA-3.0-2.5-2.0-1.0] from Wikimedia Commons


To continue to explore the factors that contribute to the collapse of a society; to learn how archaeological evidence is gathered and interpreted.


In this two-lesson series, students find out about the social changes that caused the collapse of important ancient civilizations in Central America, Mesopotamia, the southwestern United States, and western Africa. They also learn about other factors that cause major social changes and about prerequisites for a society’s survival.

Collapse 1: Why Civilizations Fall forms part of the story of human society. Students already should be familiar with the origins and importance of rules, laws, and social customs as well as the concept and some causes of social change. The lesson builds on ideas covered in earlier grades such as those found in Science NetLinks lessons at the 3–5 level, including Artifacts 1: What Can We Learn about Artifacts and Artifacts 2: Artifacts in Context. In grades 9–12, students will learn more about the types, causes, and complexities of social change, using databases to identify trends and relationships. Middle-school students are capable of imagining themselves living in other cultures and should be able to identify factors in social change as well as constant patterns in family and community life.

Collapse 2: Interpreting the Evidence extends the information in Lesson 1 and offers useful information and activities that help students learn about the ways that scientists learn about civilizations that have disappeared, archaeological issues, methods, evidence, and types of measurement. It addresses issues of values and attitudes, particularly the importance of honest, clear, and accurate record keeping; and the fact that different explanations can be given for the same evidence.

Planning Ahead

If the whole class cannot work online at once, print out and duplicate the following pages from the Collapse: Why Do Civilizations Fall? website:


Review with students the material they learned in Collapse 1: Why Civilizations Fall about the study of ancient civilizations.

Ask students:

  • How did scientists find out what the civilization was like and why it ended?
  • What types of evidence do archaeologists use?
  • Do you think that interpreting that evidence is easy? Why or why not?

If you plan to do the Garbage-ology activity in class, bring out a few bags of garbage and show them to the class.

Ask students:

  • What do you think you could learn about someone from looking at their garbage?

Tell students that they will learn more about archaeological evidence—how it’s found, how it’s interpreted, how it’s dated, and what scientists learn from it. Tell them that they will find out what garbage can tell them about people, their activities, and their lifestyle.


Read the following pages about archaeological evidence and interpretation in class or assign them as homework, followed by class discussion.

Finding and Interpreting the Evidence

Ask discussion questions such as the following:

  • What kinds of archaeological evidence do scientists use? (Pottery shards, bone fragments, lines and discolorations in the soil, and small broken pieces of stuff.)
  • What is meant by relying on context for clues about this evidence? (Context means space—where the artifact is found and what’s with it—and time—how old the item is and how deep in the ground.)
  • What factors make archaeology difficult? (The size of sites, such as Hazor in today’s Israel.)
  • What techniques help scientists to interpret evidence? (Scientists often use what they know to interpret what they don’t know, though this can be risky.)

Dating the Evidence

Ask discussion questions such as the following:

  • Why is accurate dating important? (Dating enables scientists to put events and objects in sequence and revise earlier conclusions to make them more accurate.)
  • What is meant by “absolute” and “relative” dating methods? (Absolute dating gives a specific date of material, plus or minus a margin of error. Relative dating puts things in a sequence rather than absolute dates.)
  • List and describe the main dating methods. (Carbon-14 dating [C-14] is a method of absolute dating based on measurement of radioactive decay of the C-14 atom. All living beings have a mix of radioactive C-14 and nonradioactive C-12 atoms in their organic material. When they die, they stop assimilating C-14. Since the C-14 rate of decay is constant, this is a very accurate way to measure age. For information on Obsidian hydration dating, Seriation, and Dendrochronology, see the Dating the Evidence page.)


Set up and conduct the Garbage-ology activity. Direct students to read the Garbage-ology page from the website. Make sure that they understand the project’s goals and process. Then create space on the floor or on large tables, put down drop cloths, divide the class into groups (optional), and distribute bags of garbage, rubber gloves, and additional garbage bags to each group. Ask each group to use the Secrets of Garbage student sheet to note the answers to the questions below. (Student answers to these questions will vary.)

Ask students:

  • What was in each garbage bag (list of contents)?
  • What activities do you think took place in the household, based on your evidence?
  • Who carried out these activities—an individual, a group, a family?
  • What room do you think each bag came from?
  • How did you reach your conclusions?

Discuss the Garbage-ology activity in class, recording students’ findings and speculations in a chart on the board. Point out the importance of accurate records and the fact that interpretations of the same evidence may vary, with each interpretation equally defensible.


Have students look at the final page of the website, Touching the Past.

Summarize the material and assess student understanding by asking questions such as the following:

  • What kinds of internal and external factors can cause civilizations to fall?
  • If changes like these occurred today, are we better equipped to handle them than ancient peoples were?
  • What are the important factors that a society needs to survive?
  • How do scientists find out what happened to ancient civilizations?
  • What kind of evidence do they use?
  • How do they interpret that evidence?


Ask students to choose individual or group research topics related to archaeology, using the Related Web Sites listed throughout the website and those listed on the page called Related Resources. Students may summarize their findings in written reports, class presentations, or a classroom exhibit.

As a class activity, create an exhibit of evidence from your classroom that students think might survive for archaeological investigation in the future.

Ask students:

  • One thousand years from now, what archaeological evidence do you think might survive from our classroom?
  • Taking each item one at a time, how do you think that future archaeologists might interpret each item?
  • How accurate or inaccurate would those interpretations be?
  • Which objects do you think might be most confusing to them?

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Lesson Details

Grades Themes Type Project 2061 Benchmarks National Science Standards

Other Lessons in This Series