Back to Teachers Home

NOVA scienceNOW: Emergence

Viewing Ideas

Before Watching

1. Identify animals that live or travel in groups. Many kinds of animals self-organize into groups and travel together. Have students brainstorm the names of some of these animals (e.g., birds, fish, whales, ants, and humans). Then ask how this collective behavior might help each group of animals (for example, bird migration aids a group in getting from one place to another; schooling provides fish protection through safety in numbers).

2. Generate three principles of emergent group behavior.

   Ask students what kind of simple rules the individual animals mentioned in Question 1 might be following as they gather in their groups. What does each individual do to contribute to the behavior pattern of the whole group? (The individuals keep moving; they move in the same direction; and they stay a certain distance away from those around them.) Tell the class that this group behavior is called emergence. Emergent behavior is determined from the "bottom-up" behavior of individuals—the individuals interacting with each other in simple ways, rather than from a set of "top-down" rules—a set of directions "imposed" by someone other than the individual. Make a two-column chart on the board. Label one column "Top-Down Rules" and the other "Bottom-Up Behavior." Have students brainstorm "top-down" and "bottom-up" systems of organized group behavior that happen during the school day or in their own life each week. Record their answers on the chart.

   Top-Down Rules	Bottom-Up Behavior
   Stopping at a traffic light	Noise level in the cafeteria
   Taking a test or exam	Walking through the halls to class
   Line dancing in physical education class	Getting on and off the school bus
   Playing a team sport	Walking into school assembly

   As a class, generate and examine principles of emergent group patterns. For example:

   • There is no hierarchical, top-down control or rule directing the overall group.

   • Individuals in the system determine and follow a few simple rules.

   • The interaction of the individual units following simple rules leads to an emergent group pattern.

3. Find the Latin root and the dictionary definition for the term emergence. Pair students and have each pair find the Latin root and dictionary definition of emergence. Or, you may provide students with this information. (emergere: To rise out or up. Definition: To rise or come from something.) Have pairs generate a definition for emergent group behavior. (Large-scale behavior that develops from small-scale rules and interactions, creating a group pattern.)

4. Predict patterns that would emerge from following simple rules. Ask the class to identify the pattern that would emerge if:

   • students stand around the classroom and walk along the nearest wall to their left toward the nearest corner. Once at the corner, they would face the center of the classroom, walk toward the center, and stop just before bumping into a classmate. (The class would form an "X.")

   • everyone walks randomly around a room. When they get close to another person's back, they follow that person. (After a time, people will be walking in a circle.)

   • the class stands shoulder to shoulder in a straight line, all facing the same direction. The first person in line steps forward two feet. Next, each successive person steps forward one foot more than the person who went before him or her until the middle of the line is reached. Then, the rule changes. Now students move forward one foot less than the person who went before. (A V-shaped pattern would form.)

After Watching

1. Identify similarities in emergent behavior of living and nonliving things. Copy the chart below or draw it on the board. Divide the class into teams. Assign each team a row and ask them to identify what the three groups have in common and two rules that individual units (living or nonliving) follow to form the group behavior.

   Emergence in Nature	Emergence in Humans	Emergence in Nonliving Things
   Flock of flying birds	People in traffic	Sedimentary rock formation
   School of swimming fish	People boarding a crowded train	Stalactites
   Swarm of bees at a hive	Crowd of people walking into an elevator	Sugar crystal formation
   Colony of ants	A crowd of people crossing a street	Iron filings responding to a magnet.
   Ants working in an ant colony	People dancing on a crowded dance floor	Molecules joining to form more complex molecules (such as DNA assembly)

   Have teams share their answers. (Each team's answers should include information related to the following general topics: The actions are controlled by rules affecting the individuals. The behavior of the whole group is more than the sum of the parts.)

2. Invent an emergent-behavior board game. This may be a classroom or homework assignment. In the segment, the relationship of computer checkers games and emergence is discussed. Divide the class into teams, and have each one develop a board game similar to checkers. In the game, players should move game pieces by following a few simple rules. The goal could be to create a large-scale pattern, such as a particular shape in the center of the board that is not inherent in the small-scale moves but that results from a series of small moves. Such a game demonstrates that order can emerge from disorder when individual pieces follow simple rules.

3. Design emergence posters. Divide the class into groups, and have them research, make, and present a poster on one of the following examples of emergence: bird migration; ant colonies; firefly blinking patterns; salmon migration; and traffic jams. Have students include answers to the following questions:

   • What behavior emerges from individuals following simple rules?

   • What are some simple rules individuals follow that lead to an emergent pattern?

   • How is the large-scale or group behavior different from that of the individuals?

   • Give examples of how small-scale changes can lead to big changes or problems.

   • How can randomness sometimes lead to some group stability and order?

   • Does the emergent behavior aid the group? If so, in what ways?

4. Grow crystals and consider nonliving emergence. The program notes that scientists are studying whether life on Earth emerged from simple molecules that arranged themselves into something living. Certain molecules under specific conditions can sometimes form increasingly complex structures. By growing crystals, students can observe the self-assembly of chemical units and the emergence of a more complex structure. The crystal grows—or self-assembles—because of the chemical properties of its subunits. It grows when the constituent particles precipitate out of solution and bond to form a regular lattice to which particles can continue to connect. Have students grow sugar crystals.

   Procedure

   1. Boil 1 cup of distilled water. (NOTE: Take precautions when working with boiling water.)

   2. Carefully pour the water into a heat-resistant glass container, such as a Mason jar.

   3. Add five drops of food coloring.

   4. Gradually add refined white sugar, stirring in about a teaspoon at a time. Continue until the sugar stops dissolving. At this point—when the solution is saturated—the sugar will begin to collect at the bottom of the jar. You may be able to add as much as three cups of sugar to your water.

   5. Tie the end of a piece of string to a metal paper clip (not coated in plastic). Tie the other end to the middle of a pencil. Place the string and paper clip into the jar. Wrap the string around the pencil until the bottom of the paper clip hangs in the middle of the liquid.

   6. Tape the string in place on the pencil, and set the pencil across the middle of the jar opening.

   7. Cover the jar opening with plastic wrap, and place it where it will not be disturbed.

   8. Check the paper clip every day and note any changes.

   9. After two to three days, have students share their observations and discuss how the activity relates to emergence. (Answers may include: Individual sugar units, or molecules, bond in a regular pattern, forming a lattice of sugar crystals that has a "new" structure not inherent in the individual units.)

Web Sites

NOVA scienceNOW
www.pbs.org/nova/sciencenow/3410/03.html
Offers emergence-related resources, including additional activities, streamed video, and reports by experts.

Ask a Scientist: Growing Sugar Crystals
newton.dep.anl.gov/askasci/chem03/chem03421.htm
Contains tips and recipes for growing sugar crystals.

Emergence
necsi.org/guide/concepts/emergence.html
Defines emergence and provides examples of emergent systems.

Books

At Home in the Universe: The Search for Laws of Self-Organization and Complexity in the Universe
by Stuart Kaufman. Oxford University Press, 1996.
Relates the way units self-organize into systems to mathematics.

Emergence: From Chaos to Order
by John Holland. Perseus Books, 1998.
Outlines how emergence works, including a discussion about how simple rules and parts can generate a more complex whole.

Hidden Order: How Adaptation Builds Complexity
by John Holland. Addison Wesley, 1998.
Describes step by step the ways agents interact and result in an organized system with properties different from the individual agents.