Tragedy of the Commons 5E

A great way to teach Tragedy of the Commons is with a “fishing” activity.  There are many ways to run this simulation that are wonderful. Some teachers use goldfish crackers, some use M&Ms, and some use reusable beads. I use colored marshmallows, because they’re the cheapest “food” option for my large classes.

Colored mini-marshmallows are the cheapest way to do the lab with food items.

This is my “Happy Fishing” 5E. It is taken from many sources and meshed together with questions that help lead the students into learning about resource use and depletion.

In a good 5E, the title of the lab doesn’t give the concept away. Our students are bright and will google the title “Tragedy of the Commons” on their phones to make sure they get the right answers. Our brightest are often the most uncomfortable with inquiry.


In the “Engage” section, students discuss what are resources that we all share.  Ask for volunteers and acknowledge their answers with a “thank you”, but don’t correct them. Tell them that you aren’t going to say if they’re right or wrong right now.  We will go back to the question and make corrections at the end of the 5E. Remember, don’t use the term “Tragedy of the Commons” yet.

Many times, I will have two separate copies.  One with Engage and Explore  and Explain and then the other with Elaborate and Evaluate.  This prevents students from looking ahead to try to get the “right answers”.


Supplies needed per group of 4.

Divide students into groups of 3 or 4.  Write how much each color of “fish” (marshmallow) is worth on the board and have the students copy on their data sheet.  I try to estimate which color I have the most of in the bag and make that color worth the highest amount as students tend to make that color reproduce (if they’re strategic).

Written on the board for students to copy down.

Tell the students that they are competing with each other for extra credit. The winner of each group gets extra credit and the winner (most $ earned) for the class earns more extra credit.  Read over the rules with the kids. You will find that many don’t listen as they’re intent on figuring out how to get the extra credit.

Demonstrate how to make a “net” using tape and straws and a paper towel boat. While they’re making their nets and boats, load up their plates with 5 marshmallows of each color.

Students make a net with a piece of tape between two straws.
A piece of paper towel is their “boat”

Remind them of the rules. Then, “ready, set, fish!”. Time them for 30 seconds and yell “stop”.

You will find that half the groups have depleted their ocean.  I say “now I will come and add babies to your ocean. Two babies for each two of the same color that’s left in the ocean”.

This is when the groups who depleted their ocean go “oops”. I say “for this round only, you may choose to throw some back into the ocean”. They will, but many will have a hard time deciding who gets to throw back fish and they usually won’t throw back very many.

The following video shows my students at the beginning of the lab and how I handle the first year when kids deplete their oceans:

Tell them to fill in their data charts for Year 1.  There are 3 charts to fill in for Year 1.

Remember, this is inquiry so don’t discuss the term “Tragedy of the Commons” yet. Let them figure out the concept about resource depletion before giving them the term. This is called constructivism and is how students best learn and retain information.


Students who left behind some fish


Students who planned well and let their fish reproduce.


Example data


The explain portion is where students work through guided questions in order to discover the scientific concept on their own. Don’t mention the term “Tragedy of the Commons”. Vocabulary and terms come later.

Help the kids with certain questions by asking if any of them fish and what the laws/regulations are.  Most kids have at least a couple of kids who fish and know the answers.

Students will write a Statement/Claim about how shared resources can be depleted and how to sustainably manage them.

This is the time in a learning cycle that you check for understanding. Go around to each group and quickly read the statements. Clear misconceptions.

Students may struggle with this task at first, but will get used to it later with more inquiry or 5Es. Be careful not to give away too much information. The more that they can struggle with and then reason out themselves, the better they retain and understand the information.


Students will watch 3 videos that help them understand Tragedy of the Commons in more detail and how its used in real life.

This video shows how rules and regulations are enforced:

This video reinforces the concept of Tragedy of the Commons and solidifies how people need to work together:

The video discusses other commons beyond just fishing:

After these videos, have students go back to the ENGAGE section and make corrections about commons.  Make sure kids know that a commons is PUBLIC resources, not private. Food, oil, gasoline, and private land do not work. If they say “forests”, make sure they know to write National Forest on an FRQ since much forested land is privately held.

Water is trickier. In some places (like the Eastern US) water is a commons, but in the Western US, there are complicated water rights. But, cities may own water rights but manage the rights for all the cities so the water functions as a commons.  But, privately owned wells or water from streams and rivers aren’t a commons.


The evaluate section here isn’t very long as it doesn’t need to be. Kids need to practice succinctly writing and being able to get the point across with detail without writing too much. This is practice for FRQ writing.



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