Chapter 3, “Clean Up Your Spills!”, helps students
approach and develop strategies for dealing with complex
problems. These problems often do not have clear answers because
they involve competing constraints. For example, oil spills are
complex problems to solve. Solutions involve several
technologies. The questions of which technology to use and when
to use it do not have clear-cut answers. The solution depends on
several competing constraints such as type of oil, size of
spill, proximity to the coast, and cost. Students will analyze
these constraints and learn how to explain the choices they
make.
In the Engage activity, When Solutions
Seem Impossible, students will read a dialogue between two
engineers and think about competing constraints. They share
their prior thinking about constraints and how those constraints
might drive solutions in opposite directions.
In the Explore activity, Recovery Time,
teams of students make a model oil spill and determine how fast
they can remove it compared with the efficiency of removal. They
make only preliminary interpretations of the data they collect.
During the Explain activity, Possible
versus Impossible, students read the field notes of the
engineer from the Engage activity. These notes show a worked-out
example of how to make sense of a recovery rate versus recovery
efficiency graph whose data come from the Explore activity.
Students use this model to construct an explanation for their
data from the Explore activity.
In the Elaborate activity, Simulate
and Save, students read about other oil spill cleanup
technologies. Then they use a computer simulation to understand
how each technology affects the oil spill. Students apply what
they learned from the Explain activity to form an explanation of
how each technology works.
Finally, in the Evaluate activity, Choosing
a Solution, teams select a set of constraints, which drives a
solution to the oil spill cleanup in a particular direction.
Students explain their solution to a group of stakeholders.
Before beginning this chapter, students should have completed
the first two chapters of this module. It would be helpful if
they had some knowledge about data tables, making bar charts,
calculating simple percents, and graphing x-y data.
However, you can provide that information during the activities
if necessary. Students should also have basic computer skills,
as they will be using an interactive computer simulation during
the Elaborate and Evaluate activities.
Students may harbor misconceptions about the material they
will be studying in this chapter. We list some of these
misconceptions in this section. Do not take time to go through
them as a list of lecture topics for your students, but rather
use them to inform your teaching as the misconceptions emerge.
Many activities included in this chapter work to expose
misconceptions and help students develop better mental models.
The best answer means the same thing to everybody.
Solutions to complex problems often involve compromise among
several solutions or a blend of solutions. The solution that
one group advocates may not be the solution that a different
group supports. It is natural for middle school students to
believe that everyone thinks as they do. With time and
exposure to multiple solutions, students learn to incorporate
alternative views into solutions to complex problems.
All relationships between variables are linear and
positive. Linear, positive relationships graph as a straight
line with a constant, positive slope. These graphs are common
in school settings, but certainly are not the only ones found
in nature, business, and engineering. Many relationships graph
to curved lines and many form inverse relationships. With
exposure and practice, students will not jump to the
conclusion that as one variable increases the other also
increases by a constant proportional amount.
Problem solutions always have one correct answer.
School experience often teaches students that there is one
correct answer that receives full credit. In real-world
settings, this is often not the case. Problem solutions often
vary depending on physical constraints and the subjective
beliefs or political sway of stakeholders.
Disperse is the same as remove. Dispersing oil
(spreading it out) does not remove or convert the oil into
something else. In dispersing oil, the amount of oil remains
the same. Dispersing redirects the oil from storage barrels
and landfills to the water column or ocean floor. Over time,
oil that is dispersed can be converted to organic by-products
by oil-eating organisms.
One must get it right the first time. School
experiences can reinforce the idea that only right answers
count and that making mistakes along the way isn’t common.
In fact, engineers reach solutions in a series of steps. Those
steps often involve mistakes. Engineers learn from those
mistakes and move forward toward a final solution. Engineers
view themselves as works in progress.
The Explore activity is more material-intensive than the
other activities in this chapter. You may need some time to
collect the materials needed for this activity. It is best to
conduct this activity in a room with sinks and access to water.
For the Elaborate and Evaluate activities, you will likely
need access to computers for two class periods. Be sure to
reserve computers or a computer lab in advance of these
activities.
The Materials and Advance Preparation sections for each of
these activities provide more information about the necessary
preparation.
