WHERE DOES ALL THAT STUFF GO?
Heather McPherson
32
The Science Teacher
M
aterials science—the science of stuff—has made
our lives better by making it possible for manufacturers to supply us with products. But, as a teacher,
I’m dismayed that young people enjoying countless consumer goods don’t fully understand that much of it ends up
in the dump. Landfills and dumps attract vermin, generate
leachates (including heavy metals from electronic gadgets),
and release greenhouse gases such as methane. Garbage finds
its way into our waterways, harming wildlife and creating
toxic pollution.
Students have misconceptions about materials use. Many
may think using bottled water, for example, is harmless because they recycle the plastic empties, but they fail to consider
the resources and energy used to produce, transport, and recycle something that, in any case, is superfluous in a city that
has safe drinking water.
This article describes a series of lessons in which students
investigate the technological and engineering ingenuity involved in making materials—and also the environmental
ramifications. The aim is to equip students to make informed
choices about materials use and disposal. The unit addresses
the technology and engineering of materials, including plastics, ceramics, wood, metals, alloys, and composites. The
driving question is “How do we safely dispose of all this
stuff?” As part of the unit, students act as consultants to help
the school green club create advertising that informs the student body about materials, packaging, and the garbage produced as well as the concepts of reduce, reuse, and recycle.
The unit, written for five 75-minute classes, aligns with the
Next Generations Science Standards (NGSS Lead States 2013;
see box, p. 37).
Day 1: Introduction
Step 1: Engage students in learning
Following the principles of Ambitious Science Teaching
(Windschitl et al. 2012) (see sidebar and “On the web”), step 1
helps students see that humans manufacture stuff that often
ends up in the wrong place, damaging the ecosystem. Students entering the classroom see the question “What are we
doing with all of our garbage?” on the smartboard along
with images of the Great Pacific Gyre (huge floating garbage
patch), including pictures of seals, sea turtles, and seabirds
struggling to escape. For 20 minutes, the teacher asks students questions about the images:
◆◆
Where does all that garbage come from?
◆◆
What is the primary source of garbage in the pictures?
◆◆
◆◆
How did all that stuff end up in one location in the
Pacific Ocean?
How can we reduce the amount of garbage in the
ocean? On land?
Core practices of Ambitious Science
Teaching
1. Engaging students with important science ideas;
2. Eliciting students’ ideas and making visible what
students currently know about the science being
taught;
3. Guiding sense-making talk around investigations
and other kinds of lab activities or readings to support ongoing changes in thinking;
4. Developing evidence-based explanations by scaffolding students’ efforts to put everything together
near the end of a unit. (See “On the web.”)
◆◆
What is all the garbage made of? Do you think it was
recyclable?
We discuss how ocean currents concentrate garbage in
certain locations. We also discuss plastic water bottles: Invariably, some students have them in their school packs.
Step 2: Probing background knowledge
This step elicits students’ prior understanding and ideas
without evaluating or correcting their responses. The teacher
displays examples of plastics, metals, alloys, ceramics, composites, and various woods, then asks
◆◆
How are plastics made?
◆◆
Can you see a difference in the plastics?
◆◆
Are all plastics recyclable?
◆◆
What is an alloy?
◆◆
What are common uses of metals? Alloys?
◆◆
◆◆
◆◆
What material is used on airplane exteriors? In
bicycles?
Where do we use ceramics?
Concrete and high-tech baseball bats and hockey sticks
are examples of composites. Can you suggest what a
composite is?
Students can be pressed for further discussion and can be
asked to elaborate on their explanations, which the teacher
puts on the board, grouping and categorizing them to assist
understanding.
Step 3: Collecting and making sense of data
In this step students develop and then test questions and/
or predictions about materials through challenges and
November 2016
33
FI G U R E 1
Common materials and their characteristics.
Material
How it
is made
Common Advantages Disadvantages
uses
to usage
to usage
Causes of
degradation
Methods of
safe disposal
Plastics
Thermoplastics
Thermosetting plastics
Metals and alloys
Ceramics
Composites
Wood & modified wood
problems. Each group of three students is given a table
(Figure 1) to fill out and can use a laptop, personal devices
(for internet research), and textbooks. As groups work, the
teacher circulates, probing, restating student conversations,
and clarifying misconceptions. Next, in class discussion, we
summarize what students have written on their worksheets
and deal with misconceptions. Students are told to address
at least the first four materials on the table by the next class
period if they haven’t already done so.
Day 2: An analysis of common materials and
their disposal
We discuss students’ progress with the table and give them
another 30–40 minutes to complete it. Students are asked to
share the information from the table that they worked on in
the previous class as a whole-class discussion. A blank summary data table can be posted on the board or on a smartboard. The first half of the table is completed using student
responses according to class consensus.
Step 4: Developing evidence-based
explanations
This step helps students alter their preconceptions by developing complex, evidence-based explanations. Some common
preconceptions include the notion that all plastics are recyclable (only thermoplastics are recyclable), putting an object
in recycling absolves one from further responsibility, that the
matrix is the weaker portion of a composite, whereas it is really the component that surrounds the reinforcement (for example, adobe bricks use clay or mud as the matrix and straw
as the reinforcement).
Students develop evidence-based explanations through
their conversations with their groups and during class discussions. During both the small group and class discussions, the
teacher probes, restates, and orients students to each other’s
34
The Science Teacher
ideas and to the instructional goal. For example, if a student
claims that all plastic is recyclable, the teacher can press the
student by asking: What are the different types of plastic?
What is the main difference between them? How would
this difference affect our ability to heat and break down
each plastic? The explanation, based on the evidence in their
table, is that if thermosetting plastics remain permanently
hard, then would it be possible to recycle this type of plastic?
The teacher could refer to the driving question at this point:
“How do we safely dispose of all this stuff?”
In the final 10 minutes of class, the teacher explains the
homework assignment. In this Environmental Awareness
Project (see “On the web” for the assignment handout), students develop an advertising campaign to raise awareness
about the environmental impacts of packaging materials.
Students are instructed to make a poster that focuses on
their choice of one type of packaging. They research advantages, disadvantages, daily uses, and disposal methods
of the packaging. The poster (examples, Figure 2) must address the driving question, “How do we safely dispose of all
this stuff?”
Students can work alone or in groups of two or three. If
time allows, students could complete this part of the activity in class. Students present the poster in a gallery walk on
Day 4 of the unit in the context of a school awareness campaign commissioned by the school green club.
Day 3: Calculation of ecological footprint
Step 1: Introduction: Engage students in learning
In this segment, students connect the idea of materials with
their disposal. Students examine the importance of reduce,
recycle, reuse, choices we make about food, water use, and
land use and the effect these choices have on the ecosystem
(Heddings and Frazier 2009).
Materials Science and the Problem of Garbage
FI G U R E 2
Student posters.
Student posters each focus on one type of packaging—and how to dispose of it.
The teacher first asks students questions such as:
◆◆
How would you describe food packaging at the grocery
store?
◆◆
What fruit do you like to eat?
◆◆
Where does that fruit come from and how is it packaged?
◆◆
◆◆
◆◆
◆◆
How does the fruit get from the place it is grown to your
table?
What type of bags does your family use when grocery
shopping?
What are the choices families have when buying soft
drinks, baby diapers, or household cleaning products?
Do some products have more environmentally friendly
packaging than others?
Answers are recorded on the board.
Next, we look at photos of the typical food eaten by families
in one week around the globe (Daily Mail 2013). Students are
asked:
◆◆
◆◆
◆◆
◆◆
How do North Americans package their food?
Europeans? Africans?
How do packaging choices affect the quantity of
garbage?
How does land-use requirements of eating meat
compare to a vegetarian diet?
What are the merits of eating locally produced foods?”
Again, responses are recorded on the board.
Step 2: Probing background knowledge
Students are questioned to elicit prior understanding about
ecological footprints without evaluating or correcting their
answers. Answers are recorded on the board. The term ecological footprint is not introduced until the class discussion
is complete. Students are asked to rephrase other student
thinking about how the information on the board could affect global systems.
Step 3: Collecting and making sense of data
The teacher shows students how to use the ecological footprint calculator (see “On the web”) and explains the accompanying assignment (see “On the web” for the student handout and for an example of one student’s work). The carbon
footprint calculator helps students develop their questions
and predictions about ecological footprints and helps them
test their predictions through inquiry, challenges, and problems. Students work independently for the rest of the class
period, each with a laptop.
The online calculator asks a series of multiple-choice
questions for students to answer. The program covers various topics, including transportation, food, household habits,
and household waste. The calculator also includes tips to reduce one’s overall footprint. Students need about 30 minutes
to fill in the online questionnaire.
Step 4: Developing evidence-based
explanations
Students rank and compare their own ecological footprints
with that of the school. This helps make the activity personal
and relevant. The ecological footprint assignment (see “On the
web”) asks students to develop evidence-based explanations
November 2016
35
for human impacts on the environment and possible solutions.
Students may complete the assignment in class, which takes
50–60 minutes, but most prefer to do it as homework, which
gives them time to develop higher-quality explanations.
Day 4: Gallery walk of poster assignments
Step 4: Developing evidence-based
explanations (continued)
Students set up the posters they made for the Environmental
Awareness Project around the classroom, and we do a gallery
walk. Students are asked:
◆◆
◆◆
What technologies are used to produce your material?
What is the environmental impact during production
of the material?
◆◆
How is your material safely disposed of?
◆◆
Is it possible to extend the life of the material?
◆◆
What can be done to reduce the amount of garbage
created by your material?
Posters are evaluated with constructive feedback provided. During Day 4, there is time for a unit review to prepare
for the upcoming evaluation.
Day 5
Step 4: Developing evidence-based
explanations (continued)
Students alter their preconceptions by developing complex,
evidence-based explanations based on investigations from the
ecological footprint calculator activity. The class begins with
students sharing their data/conclusions with one other group
for 10–15 minutes. Next comes a 10– to 15–minute guided
class discussion with student responses written on the board.
Students can be prompted to consider each other’s thinking
by asking: “Do you agree with what Student A said? Why?”
Students can also be pressed for explanations: “Group A and
B, your conclusions differ. Can you explain your thinking?”
Evaluation for learning [can occur the
next day if necessary]
The teacher gives a 40-minute pencil-and-paper
test. Students are asked to reconsider the Great
Pacific Garbage Patch in light of what they have
learned about materials and their own ecological
footprints. Test questions are open ended and focus
on materials, lifecycle costs of production, usage, safe
disposal, and impact of consumer choices on global
ecosystems. Students also submit the ecological footprint assignment.
36
The Science Teacher
Conclusion
This unit has been an effective method to teach global garbage issues related to society’s reliance on materials made possible by engineering and technology. The unit incorporates
problem-based learning and inquiry-based lessons and follows the practices of Ambitious Science Teaching. Students
find the unit engaging, and, afterward, I’ve noticed that they
bring far fewer disposable water bottles into my classroom.
Mission accomplished. ■
Heather McPherson ([email protected]) is a senior
science teacher at Laval Senior Academy in Laval, Quebec, and
is working on a PhD at McGill University in science education.
On the web
Ambitious Science Teaching, University of Washington: http://
ambitiousscienceteaching.org/get-started
Ecologial Footprint Assignment handout and student work
sample: www.nsta.org/highschool/connections.aspx
Environmental Awareness Project: www.nsta.org/highschool/
connections.aspx
Zero footprint youth calculator: http://calc.zerofootprint.net/youth
References
Asghar, A., R. Ellington, E. Rice, F. Johnson, and G.M. Prime.
2010. Supporting STEM education in secondary science
contexts. The Interdisciplinary Journal of Problem-Based Learning
6 (2): 85–125.
Bell, D. 2012. IBSE: The roles of assessment and the relationship
with industry: A reflection. IAP conference proceedings,
Finland. http://bit.ly/2aZYJ7g
Daily Mail. 2013. The Great Global Food Gap: Families Around
the World Photographed With Weekly Shopping as They
Reveal Cost Ranges from £3.20 to £320. May 5. http://dailym.
ai/1gd74zt
Heddings, K.S., and W.M. Frazier. 2009. Shrinking our footprints.
The Science Teacher 76 (6): 25–28.
NGSS Lead States. 2013. Next Generation Science Standards: For
states, by states. Washington, DC: National Academics Press
Windschitl, M., J. Thompson, M. Braaten, and D. Stroupe. 2012.
Proposing a core set of instructional practices and tools for
teachers of science. Science Education 96 (5): 878–903
Materials Science and the Problem of Garbage
Connecting to the Next Generation Science Standards (NGSS Lead States 2013).
Standards
HS-ESS3 Earth and Human Activity
HS-ETS1 Engineering Design
Performance Expectations
The chart below makes one set of connections between the instruction outlined in this article and the NGSS. Other
valid connections are likely; however, space restrictions prevent us from listing all possibilities. The materials, lessons, and
activities outlined in the article are just one step toward reaching the performance expectations listed below.
HS-ESS3-1. Construct an explanation based on evidence for how the availability of natural resources, occurrence of
natural hazards, and changes in climate have influenced human activity.
HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.
HS ETS1-1. Analyze complex real-world problems by specifying criteria and constraints for successful solutions.
Dimension
Name and NGSS code/citation
Specific Connections to Classroom
Activity
Science and
Engineering
Practices
Constructing Explanations and Designing Solutions
• Construct an explanation based on valid and reliable
evidence obtained from a variety of sources (including
students’ own investigations, models, theories,
simulations, peer review) and the assumption that theories
and laws that describe the natural world operate today
as they did in the past and will continue to do so in the
future. (HS-ESS3-1)
• Design or refine a solution to a complex real-world
problem, based on scientific knowledge, studentgenerated sources of evidence, prioritized criteria, and
tradeoff considerations. (HS-ESS3-4)
Students research materials used buy
society, and the safe disposal of these
materials.
Students explain the effects of lifestyle
choices on individual ecological footprints
by using an online ecological footprint
calculator.
Students act as environmental consultants
by developing a research poster presented
in a gallery walk that is designed to
educate others about the problem of
packaging and garbage.
Asking Questions and Defining Problems
• Analyze complex real-world problems by specifying
criteria and constraints for successful solutions. (HS-ETS1-1)
Disciplinary
Core Ideas
ESS3.A: Natural Resources
• Resource availability has guided the development of
human society. (HS-ESS3-1)
ESS3.C: Human Impacts on Human Systems
• Scientists and engineers can make major contributions
by developing technologies that produce less pollution
and waste and that preclude ecosystem degradation.
(HS-ESS3-4)
ETS1.A: Defining and Delimiting Engineering Problems
• Humanity faces major global challenges today, such as the
need for supplies of clean water and food or for energy
sources that minimize pollution, which can be addressed
through engineering. These global challenges also may
have manifestations in local communities. (HS-ETS1-1)
Crosscutting Cause and Effect
Concept
• Empirical evidence is required to differentiate between
cause and correlation and make claims about specific
causes and effects. (HS-ESS3-1)
Student groups discuss and analyze the
global problem of waste and the impact
on land and sea resources.
Students complete a research poster
and presentation about the effects of
materials production and safe disposal.
Students evaluate their personal lifestyle
choices to understand their ecological
footprint.
Students act as environmental consultants
to inform the school body about the
causes and effects of materials production
and waste disposal.
Students analyze their lifestyle choices
to find solutions to alleviate problems
associated with use of global resources.
November 2016
37