Lab: Tragedy of the Commons
Name: __________________
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Purpose: To observe the effects of competition on a shared resource.
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Background: The term “Tragedy of the Commons” comes from an essay by Garrett Harden written in 1968.
The “commons” refers to a common resource: one that is equally available to everyone.
When resources
are available readily to all persons, with nobody being responsible for its preservation or protection, people
tend to behave in a manner that is unsustainable.
In this modeling activity we will observe how competition
and necessity affect a common resource.
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The Situation:
You are a fisherman who must obtain enough resources to survive the year.
group of other fishermen.
Your pond is shared by a
You will use a straw to “fish” for the “catch” of M&M's.
There are enough
M&M's in your pond to support your community indefinitely with reproduction (restocking).
The more fish
you catch, the more you can eat (at the end of class).

You must supply food for your family.
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You share a fishing hole along with three other families.
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This fishing hole can only hold a certain amount of fish.

You do not know that number at this time.
You will do 4
rounds of fishing.
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After each round of fishing, you will trade who “fishes” first
so that each person has a chance to go first.
Trial 1 Procedure:
1.
The pond is the cup, the fish are the M&Ms, and the straw is the pole.
the straw until you feel you have a fish.
remove your fish.
You will fish by sucking
You then pull the straw out of the pond at that time and
YOU MAY NOT LOOK IN THE POND.
2. You have 30 seconds to fish.
You may catch as many fish as you want.
You have to catch at
least 2 fish for your family to survive.
3. After your 30 seconds, allow each member of the group to record the number of fish caught.
4. The next person fishes.
After 30 seconds, record the number of fish caught.
5. At the end of the round (all 4 people have fished or pond is out of fish) return the pond to
teacher to allow fish to reproduce.
ROUND
1
2
3
4
TOTAL
# of fish
taken by
fisher 1
# of fish
taken by
fisher 2
# of fish
taken by
fisher 3
# of fish
taken by
fisher 4
Total fish
taken per
round
TRIAL 2 Procedure:
 This time you will be allowed to talk and strategize. You will also be able to look in the pond
while you are fishing and while others are fishing.
 The pond can only hold ____ fish.
 You may remove as many fish as you wish each round.
 Record your results.
 After each round, return the pond to the teacher for “reproduction”.
ROUND
# of fish
taken by
fisher 1
# of fish
taken by
fisher 2
# of fish
taken by
fisher 3
# of fish
taken by
fisher 4
Total fish
taken per
round
1
2
3
4
TOTAL
PLEASE NOTE: Make sure you have filled out your data tables completely (table1). Leaving a square
blank IS NOT the same as recording a zero.
Leaving a blank means that you did not finish.
Writing a
zero, or a dash through the square, means that zero fish were caught.
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Analysis
Create a line graph to represent BOTH TRIALS (there are multiple lines, so you need to use colored pencils).
Make sure your graph has a title; each axis is labeled, in color, with a key! Also remember that dependent variables go
on the y-axis, independent variables go on the x-axis.
ANSWER EACH OF THE FOLLOWING QUESTIONS. You may work in groups to answer, but each student
has to turn in his or her own answers. Some questions cannot be answered by the group.
1. What happened to the common resource in Part 1?
Why?
2. Explain how you fished (your strategy) and why in Part 1.
3. Did you get different results for the common pond in Part 2?
Why?
4. Explain how you fished (your strategy) and why in Part 2.
5. Why does common usage lead to exploitation (overuse)?
6. What would be the ideal way to manage a commons?
7. If the “tragedy of the commons” is explained as the mindset “If I don’t use it someone else will”,
would this describe your strategy in the first round?
8. If a new student had joined your group in part two that had not followed the group’s “rules”, how
would it have changed YOUR strategy?
9. Think of a local commons that you are familiar with. [parking lots, bathrooms, Cafeteria,, etc.] Do
similar situations arise? Explain. HOW might those problems be solved?
10. What are some natural resources that are common resources?
11. Think of a situation in the world today that is a GLOBAL RESOURCE “tragedy of the commons”.
What is that problem, why is this resource NOT being used wisely?
12. The instructions said the pond would last indefinitely, explain how (with words & numbers)?
CONCLUSION:
Explain the “tragedy of the commons” in your own words, tell specifically how this lab illustrates
the problem and give 2 solutions for managing a common resource.
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