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NOVA scienceNOW: Emergence
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Viewing Ideas
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Before Watching
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). 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.
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Top-Down Rules
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Bottom-Up Behavior
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Stopping at a traffic
light
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Noise level in the
cafeteria
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Taking a test or exam
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Walking through the
halls to class
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Line dancing in
physical education class
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Getting on and off the
school bus
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Playing a team sport
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Walking into school
assembly
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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.
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.)
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
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.
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Emergence
in Nature
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Emergence in Humans
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Emergence in Nonliving Things
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Flock of flying birds
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People in traffic
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Sedimentary rock
formation
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School of swimming fish
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People boarding a
crowded train
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Stalactites
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Swarm of bees at a hive
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Crowd of people walking
into an elevator
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Sugar crystal formation
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Colony of ants
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A crowd of people
crossing a street
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Iron filings responding
to a magnet.
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Ants working in an ant
colony
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People dancing on a
crowded dance floor
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Molecules joining to
form more complex molecules (such as DNA assembly)
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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.) 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. 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?
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
Boil 1 cup of distilled water. (NOTE:
Take precautions when working with boiling water.) Carefully
pour the water into a heat-resistant glass container, such as a Mason jar. Add five drops of food coloring. 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. 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. Tape the string in place on the
pencil, and set the pencil across the middle of the jar opening. Cover the jar opening with
plastic wrap, and place it where it will not be disturbed. Check the paper clip every day
and note any changes. 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.
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