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EarthDay Birthday Party

Catherine Sheils Ross (Cathy)
2325 Catalpa
Berkley, MI 48072



This is an encapsulated method to teach population dynamics, conservation, and the effects of overpopulation on our planet's resources. The activities are so much fun that we now have them as our "EarthDay Birthday Party" in all of our Biology classes.

The "Popcorn Game" was originally developed at a 1979 Energy and Transportaion workshop (the Detroit Connection) at Wayne State University through the Physics Department.



Very Dry Lab:
Interdisciplinary-biology, conservation, math, social studies, business, music, drama?, and fun.


Biology Classes-any age


My three-segment lesson takes one to two 55 minute class periods, depending on how much time is spent on each part. It can all be done in one class period, if needed.

In discussing population dynamics, we focus on human population growth. The discussion includes Thomas Malthus' ideas regarding the arithmetic growth of food production and the exponential growth of the human population. Students can construct graphs to visually see the problem.

If possible, show the movie, "Popular Little Planet", originally produced by 3-2-1 Contact, and shown on Public TV in 1992. (After loaning my legal copy, having it taped over, scavenging to 3-2-1 Contact in Vermont , Public TV in Detroit and New York, I finally located a copy for $19.95 at Sunburst. This 30 minute tape is great and has a super song, "You're Not One in a Million, You're One in 5 Billion." (words enclosed) After the movie, we play the Popcorn Game.

MATERIALS: easy to set up!

Part 1: Earth's Biggest Problem/Malthusian Hypothesis

your blackboard or overhead
Malthusian Hypothesis info and population figures (Please see Appendix)

Part 2: Popular Little Planet This 3-2-1-Contact Film was developed for middle school, but we feel it's universal in age appeal.

Film-"Popular Little Planet"
Can purchase for $19.95 from:
Sunburst/Wings for learning
101Castleton Street
PO Box 100
Pleasantville, NY 1050-9961
Fax # (914) 747-4109
Phone: (914) 747-3310
Toll-Free: (800) 321-7511
e-mail webmaster@nysunburst.com

Part 3: Popcorn Game
**1-2 brown paper grocery bags-one decorated with the Earth, the USA and an "X" on your location. Label it "Earth's Resources." (food, fuel, shelter, space,.....)
**a sign for yourself on a string to wear around your neck or pin on identifying yourself as "Mother/Father Earth (or Nature).
**2 Plastic trash bags-one for reserve popcorn, and one for recycled popcorn
**popcorn (2-3 days ahead, I tell students they can earn 5 bonus points if they bring in a full unopened microwave bag of popped popcorn. You need it ready!) Bring it in to our classsroom the morning of the Earthday Birthday Party. (Otherwise they'll eat it, before you can get it. I've lost a lot of popcorn to the excuse that they or "someone else ate it".) I've also had students who work for movie theaters get surplus popcorn.
** Hot Air popcorn popper and one bag of popcorn as reserve if the donations don't arrive. (Rarely need to do. I have one in the room for occasional movies.)
** After determining how much is donated (fill the grocery bags, approximately one-two per class) or a clean trash bag and hide the extra.
** Paper towel placemats to put popcorn on.
** Paper or index cards numbered for generations (#1-16 for a class of 32 in pairs)
** Small (50 ml) and Larger (400ml) beakers to scoop popcorn.

STRATEGY/PROCEDURE: (can all be done in one very crowded day) or

Parts 1 and 2 the day before Earth Day
Replay Songfest from part 2 and Part 3 on Earth Day.

Calculate the powers of two and describe exponential growth and doubling time.
Develop a very personal understanding of what happens when exponential growth is limited by finite resources.
Understand and make projections of human population growth and consequences of overpopulation.
Become more responsible global citizens.
Have fun.

Part 1: What's Planet Earth's Biggest Problem ? aka Malthusian Hypothesis

To lead into the activities, we brainstorm the following question: "What is our Planet's greatest problem after ignorance?" (Students will offer hunger, drugs, pollution, AID's, crime, war, .... and all are correct.) Then we try to find the underlying cause of all of their suggestions and students will usually conclude that it is human overpopulation.

Next, we discuss or review Thomas Malthus's ideas on exponential human population growth and the arithmetic growth of food production. We define, discuss the consequences, and graph each. This can be done quickly by going over the powers of two in both progressions. More formalized graphing of specific demographics can be done in class or assigned for homework. ZPG has the most current numbers but I've included a few. (Pls. see Appendix.)

Part 2: "Popular Little Planet"

Show the film, "Popular Little Planet". (1/2 hour long) Have your overhead ready to put a transparancy with the words or hand out copies of our favorite song, "You're Not One In a Million...You're One in Five Billion." The song (1 1/2 minutes long) starts five minutes into the film. It is really fun if you (teacher) act out the words to the song. (like the "YMCA" song) My kids love to see the me dance and sing and generally act crazy. They sure remember it better! (They told me they even sang the song later at parties they went to.) I usually rewind and repeat the song again at the end of the viewing. You could have a discussion about the film but won't have time if you're going to do the "Popcorn Game." (I played and replayed the tape a kazillion times to get this for us-the kids remember it and ask each year when we're going to sing it again.)

Part 3: The Popcorn Game

I've greatly modified the activity that was developed during the 1979 Energy and Transportation workshop, The Detroit Connection, offered by the Physics Department at Wayne State University.

Introduce yourself as Mother or Father Earth/Nature and show them the bag (usually a brown paper bag that represents all the resources of our Planet. (Food, fuel, shelter, space.....)

Fill the bag with all the popcorn they have brought in, that you've gotten from a theater, or that you've air popped. One or two grocery bags is usually enough for a class of 30.

Hand out the generation numbers to pairs of students who have paper towel placemats on their tables. In a class of 32, you'd have 16 generations.

Go to generation "1" and scoop out 2 50ml beakers of popcorn and put it on their placemat. This represents all the Earth's resources that their generation used.
Then go to generation "2" and congratulate them on the births of their beautiful children. Ask them how much of the Earth's resources they need, if there are now twice as many people on the Planet. They will say "4 beakers-full". After giving them their popcorn, ask the third generation to identify themselves and ask them how much they need to survive. (They need 8.) As you start to go scoop-crazy, you might want to use a larger beaker (400ml) for distribution.

Each generation will need twice as much as the preceeding generation. Usually around the 6th generation, the supply cannot meet the demand, and humans go extinct. I just hand that generation what's left or give them the entire bag. When the complaints begin, Mother/Father Earth just comments that "you aren"t even born, so what's your problem??"

Then, after their anxiety level is very high and to avoid mutiny, ask the early generations if they are willing to better caretake our Planet and share the resources with the later generations. You can redistribute the popcorn so everybody gets some.

As we leave class, I replay the song, "Not One In A Million..." one last time, and we make a point of practice-what-we-preach conservation: leftover popcorn goes into a recycle bag (for compost), paper placemats into the recycle box, and no mess on the floor.

CLOSURE/EXTENSIONS: Further discussions/ activities might include...

  1. How much popcorn would be required to last through the neighboring class, assuming doubling? Through the whole school?
  2. Can exponential growth continue without limit?
  3. Compare the feelings of the early generations with those who were cheated.
  4. Options for approaching the limit can be discussed, and their social implications evaluated.
  5. Write a paper on current systems of population control i.e. China's one child policy.
  6. Professor Garrett Hardin (UC at Santa Barbara, CA) writes that "the secret of living a agood life is learning to live within limits." Write a position paper on this topic.
  7. Make "Eco-Jewelry": Get Earthday USPostage stamps and use for center of a lapel pin, earrings, necklace, or tie tacks etc., and finish with small pieces of recycled materials. i.e. bits of aluminum foil, styrofoam, paper, buttons, old jewelry. (c. C. Sheils Ross, 1996)
  8. Make Earthday or Conservation posters and display around school.
    (In MI we have a writing proficiency test for high school diploma endorsement and students bring writing samples from each class. Science writing samples might be on these topics. Please see appendix.)

Cohen, Joel E., (November 1992) How Many People Can Earth Hold?
Discover Magazine.

Rx for Planet Earth (1992)
Planet Earth: dying species, disappearing habitats
Great Decisions

Hardin ,Garrett , (April 1994)
Perpetual Growth: The Next Dragon Facing Biology Teachers. American BiologyTeacher , Volume 56, No.4,

Murphy, Elaine M., (1978) World Population: Toward the Next Century
Population Handbook by Arthur Haupt and Thomas T. Kane (Population Reference Bureau, Inc., Washington D.C.

Cox News Service
Chinese tradition favoring boys will leave society of men without wives. Naples Daily News , February 12, 1995

Sunburst/Wings for learning
101 Castleton Street
PO Box 100
Pleasantville, NY 10570-9961
Toll Free: (800)321-7511

Zero Population Growth
1400 16th St. NW, Suite 320
Washington, D.C. 20036
Internet: zpgpoped@igc.apc.org


Malthusian Hypothesis or How Does a Population Grow?

Thomas Malthus had a strong interest in the social conditions of his time in 18th century England.

Malthus' Hypothesis (1798) included the idea that the size of the human population is regulated by certain external forces. His two assumptions were: food is necessary for existence and that humans will continue to reproduce. In his own words, he hypothesized:

"I say that the power of population (reproduction) is infinitely greater that the power in the earth to produce subsistence (food) for man."

Population, when unregulated, increases in an exponential manner. Thus, it accelerates faster each year . A exponential series of numbers would be: 2, 4, 8, 16, 32, 64, 128...Each subsequent number is obtained by multiplying by a constant... in this case 2. What would the next number in the exponential series be? ______ What would a graph of these numbers look like?

Food or subsistence increases in an arithmetic manner. Arithmetic growth is much s/lower than exponential growth. An arithmetic series of numbers would be: 2, 4, 6, 8, 10, 12, 14, 16, 18,... What would a graph of these numbers look like?

So, ultimately, there will not be enough food to support the human population. Malthus proposed that wars, famines, plagues, and natural disasters would control the population. Malthus' essay also influenced the young Charles Darwin. He saw that overreproduction would lead to natural selection of those individuals best able to obtain the available resources and thus reproduce their own kind.

What do you think? But, before you decide, using the most recent demographic data, construct a graph of human population growth. Included is projected growth (at the current rate) into the next century.

Human Population Growth
Billions of People Time AD

0.3 1
0.5 1650
  1. 131 1850
  2. 516 1950
  3. 079 1975
  4. 311 1990
  5. 463 2000
  6. 978 2025
    21.161 2050
    46.261 2075
  7. 405 2100
  8. 138 2125
  9. 213 2150

**Estimates of global carrying capacities differ depending on the level of farming technology and land potential to produce food. In countries with low levels of technology , the carrying capacity estimate at 2000AD is 5.7 billion, 14.4 billion with an intermediate level, and 32.3 billion with a high level of technology. If the entire planet has high tech farming, there will be 19 "critical" countries by 2000. If there's only a low tech level, there will be 64 critical countries with over 503 million more people than they can feed. (Discover Magazine, Nov. 1992)

(For your overhead projector)

You're Not One in a Million

(from Popular Little Planet )

What's Happenin' all around us? (shrug shoulders, palms up)
Can anybody see? (point to eyes)
The population of the Earth is growing rapidly. (open arm spread)
Today it's up to 5 billion (hold up one open hand, spread fingers)
Tomorrow what'll it be?
There are lots of people everywhere (point individually)
But there's also you and me! (point to class and yourself)


You're not one in a million

(shake head wagging one finger)

You're one in 5 Billion!!!

(nod, point and show open five fingers palm)

Think, think, think, about what you do

(point each time to your head)

What if all 5 Billion do it too???

(circle with hand and open five fingers)

Come on....


("forward wave" and point to head)

THINK about what you do....ooooooo.

(point to your head)

We're using up the water, air, and land at a rapid pace
Can all these people and animals share this space?(palms up open arms encompassing everyone, then clasp hands together)
Our land is overcrowded
We're bursting at the seams(inflate cheeks and elbows out)
Will there be a price to pay (Palms up)
If we live beyond our means? (one hand slicing neck)


(choreography by Cathy, 1992)

C. 3-2-1-Contact/Sunburst

Writing Topics:

The following two writing topics are based on news articles but can be utilized independently. Most of the questions were written by my colleague, Barbara S. Spuhler, Berkley H.S. All of our Biology students write on them, and can include them in their writing portfolio collection.

What Should We Do?

The population of the U.S. is expected to double in the next 50 years.Knowing that overpopulation is associated with many problems, would you be in favor of population control measures in an attempt to extend that timeline? Why or why not?

If there was no choice, which of the following measures would you consider implementing ( be sure to discuss what each would achieve and possible problems related to implementation)?

a. limiting family size, number of children'
b. limiting life extending measures for the terminally ill
c. limiting immigration ( people coming into the U.S.)
d. others that come to mind

Experts Say U.S. Diet Will Change

There are forecasts that an Energy crunch will change our diet. Should efforts begin now, to steer, or change the American diet away from meat and dairy, and toward potatoes, pasta, and beans? Why or why not? (Consider placing yourself as a primary consumer most of the time, rather than farther down the food chain.) How might that help feed more people globally?

a. The advantages and disadvantages of a changed diet.
b. How such a change could be implemented within our society.
c. Problems that might be encountered in implementing such a change.
d. Your present diet: Would you be willing to change it, if you are not already eating vegetarian-like meals. Why or why not??

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