click to skip navigation Education for Sustainable Development Toolkit, version 2 point o
E S D Toolkit logo -
back to E S D Toolkit home  
Author's note
What is E S D?
Reorienting Education
Localizing the Global Initiative
Challenges and Barriers to E S D
Community Sustainability Goals
Case Study: Toronto, Canada Board of Education
Managing Change
Public Participation
Concluding remarks
Tools to Introduce the Concept of Sustainable Development
Tools to Create Community Goals
Tools to Reorient Education to Address Sustainability
Tools for Managing Change
Web resources

powered by FreeFind

This hands-on exercise puts participants in the middle of an easy-to-understand sustainability dilemma.


To introduce participants to the concept of sustainable development.


For a closer examination of the concept of sustainable development, see also the exercises Seeing Your Community Through a Sustainability Lens and S.E.E. the Links.

Group size: 4 to 36 participants.

Time Needed: 30 minutes


  • A large number of small pebbles.
  • Paper and pencils for keeping score.
  • Extension: A chalkboard and chalk.


  1. Divide the group into communities of four.
  2. Place 16 pebbles in a communal pile for each community.
  3. Explain the rules of the game:
    • The pebble pile represents a valuable renewable resource. The resource is replenished after each round of play.
    • Each community member may take freely from the resource pile each round.
    • Each community member must take at least one pebble in each round to survive.
  4. One person in each community must record the number of pieces taken by each community member in each round.
  5. After each round, count how many pebbles each community has remaining in the pile, and add an equivalent number of pebbles to the pile.
  6. Play three or four rounds, pausing after each round to find out if any community members did not survive.
  7. Play one final round, then have community members share what happened in their communities:
    • In which communities did everyone survive?
    • Which community had the most pebbles in the resource pile at the end of the game?
    • Which communities are confident they will always have enough pebbles for everyone as long as the pile is renewed? How did these communities arrive at that point? What strategies were used?
    • Was there a leader in these communities? If so, why did the community listen to that person?
    • Could these communities have reached "pebble sustainability" without communication?
  1. Compare per capita pebble ownership around the room.
    • Out of the whole room, who had amassed the most pebbles? How did he or she accomplish this?
    • Did this keep others from surviving?
    • Where do we see this type of greed in the real world?
  1. Start a discussion of the following:
    • What information is necessary to know how to manage a resource sustainably (e.g., community size, resource renewal rate, environmental carrying capacity, etc.)?
    • What is needed to actually put information into practice (e.g., leadership, communication, trust, legislation, understanding of consequences, examples of failure, etc.)?


  1. Propose that all communities are taking pebbles from one communal pile. Some communities are at war with one another, and some are unaware of the others.
    • Would the pebbles still need management? How would these factors affect the management of the pebbles?
    • Would these situations change how community members felt about adhering to their sustainable usage?
    • How might global pebble usage be managed? Write suggestions on the chalkboard.
  1. Now explain that this scenario represents the current state of our common resource, the atmosphere. Automobile and factory carbon dioxide emissions are heating up the atmosphere, causing the "greenhouse effect" and changing the ecology of the planet. Each pebble taken represents one "share" of carbon dioxide emissions generated by that person.
    • How do the communities that reached sustained usage feel about the "greedy" communities' usage?
    • How can the atmosphere be managed? Would the suggestions listed on the chalkboard be useful in this situation?
    • What are other "real life" examples of shared resource issues?


The pebbles represent a valuable renewable resource. In the United States, this game is often played with individually wrapped candies. The participants are told they can keep and eat the candies they have at the end of the game. Using candies or coins rather than pebbles helps participants understand the temptation and greed associated with this game and how it applies to the real world. The authors realize that playing with food is not culturally acceptable in many societies.

Adapted from "Greed vs. Need" in Project Learning Tree: Pre-K-8 Activity Guide, 3rd edition, American Forest Foundation, 1995, and "Why EE?" in EE Toolbox - Workshop Resource Manual, by J.F. Disinger and M.C. Monroe, Regents of the University of Michigan, 1994.

Return to Top | Next section: Drain or Sustain II