Richard Lahti

1
Student Created Excel Models To Test
Environmental Claims

• Richard Lahti
• Minnesota State University Moorhead

2
There is a need for more math in K-12 science

• Math is the 1 barrier many college students face
  in their chemistry and physics classes at MSUM,
  not science content.
• In order to make high school science accessible
  to all students , much of the math has been
  removed.
• There are attempts to reintegrate math into k-12.
• Dr. Neuhausers work.
• PKAL/QuIRK
• Other numeracy efforts.

3
Description

• Proper tire inflation vs. offshore drilling
  was a debate that could be easily modeled and
  tested. Students in an environmentalchemistry
  course created from scratch models to test other
  claims. Their models, and the broader NOS
  implications to hypotheses and theories, will be
  examined and discussed.
• http//www.time.com/time/politics/article/0,8599,1
  829354,00.html
• http//www.factcheck.org/elections-2008/the_truth_
  about_tire_pressure.html
• http//blogs.abcnews.com/politicalpunch/2008/07/fr
  om-the-fact-1.html

4
Scientific models are an essential part of science

• They are mentioned repeatedly in the Minnesota
  math and science standards.
• They are mentioned repeatedly in national
  standards.
• http//www.nap.edu/booksearch.php?termmodelsisbn
  0309053269
• http//www.project2061.org/publications/bsl/online
  /index.php?chapter11B0
• Grosslight et al. (1991) detail the most common
  misconceptions students have about models.
• Grosslight, L., Unger, C., Jay, E., Smith, C.
  L. (1991). Understanding models and their use in
  science Conceptions of middle and high school
  students and experts. Journal of Research in
  Science Teaching, 28, 799822.

5
Scientific models are not easily understood by
students
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Overlap between models and theory

• Students understanding of models should be
  related to their understanding of theories.
• Physicists use model and theory interchangeably.
  (i.e. Standard Model).
• The purpose of a model or theory is to allow for
  adequate predictions or explanations of
  phenomena.
• Both are supported by using the model/theory to
  create a hypothesis and then testing it.

7
Regurgitation of Nature of Science Concepts

• Hypothesis is an educated guess
• what does educated mean? (based off of theory)
• A theory is a hypothesis that has been tested
  many times and not been proven wrong
• (unless its evolution, then it is just what
  some people think).
• But what does tested many times mean? The
  same test over and over?
• Most of my students (MSUM) come to me
• not knowing the difference between a theory and
  law
• and most think a theory can become a law

8
Content-Free Inquiry

• Windschitl and Thompson (2006).
• Science Fair
• Stains and dyes. No ones hypothesis referenced
  solubility.
• Making a hypothesis with a model is a potential
  cure for this idea of content free inquiry.
• Windschitl, M. Thompson, J. (2006) Transcending
  simple forms of school science investigation The
  impact of preservice instruction on teachers
  understandings of model-based inquiry. American
  Educational Research Journal, 43(4), 783-835

9
Closing the learning cycle
10
Differences between subjects, teachers, creates
problems

• Physicist have the best understanding
• many of their theories are still active and being
  tested.
• Unfortunately, most of this work is in modern
  physics and beyond the high school level.
• Chemists tend to see their models of atoms as
  literal because
• Their theories have all been proven (atomic
  theory and kinetic molecular theory)
• Biologists falls somewhere in between
• big theory (evolution) is too controversial to be
  useful in teaching NOS.
• Many of their models (cells, anatomy) are
  physical.
• Genetics and predator prey provide good
  opportunities for exploring models and theories.
• Many biology theories (germ theory, cell theory)
  have also been proven.
• Justi, R. and Gilbert, J. K. (2003) Teachers'
  views of the nature of models. Int. J. of Science
  Education, 25, 1369-1386.

11
To teach all of the important aspects of models
requires

• Having a model that can be manipulated
• Multiple valid models of the same phenomenon are
  possible
• Using models to make predictions and testing
  those predictions, with subsequent revision.
• Modeling the behavior of an object or phenomenon,
  not the object itself.
• Draws on Lesh et al mathematical modeling.
• Lesh, R., Cramer, K., Doerr, H., Post, T.,
  Zawojewski, J. (2003) Model development
  sequences. In R. Lesh H Doerr (Eds.), Beyond
  constructivism Models and Modeling perspectives
  on mathematics problem solving, learning and
  teaching. Mahwah, New Jersey Lawrence Erlbaum
  Associates.

12
Some methods of model instruction show little
improvement.

• Ruebush et al in Jan/Feb JCST.
• The above black box study found many students
  misconceptions about models were unfazed by
  teaching. The researchers commented on the
  desire of students to know the right model,
  even months after the study.
• Problem there was a right answer.
• Ruebush, L., Sulikowski, M. North, S. (2009) A
  Simple Exercise Reveals the Way Students Think
  About Scientific Modeling. Journal of College
  Science Teaching.

13
The study

• Setting Liberal studies environmental chemistry
  class at MSU Moorhead.
• Pretest on Nature of Science and Modeling
• Series of activities using/critiquing models
• Final Excel activity building model
• Posttest on Nature of Science and Modeling

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The following scaffolding projects preceded the
Excel project

• 1. Using/critiquing a teacher provided food and
  water use model in Excel
• 2. Comparing several carbon footprint models
• 3. The Java Climate change model
• http//www.astr.ucl.ac.be/users/matthews/jcm/
• 4. PHET Greenhouse Effect model
• http//phet.colorado.edu/simulations/sims.php?sim
  The_Greenhouse_Effect
• After each stage, an explicit reflective
• approach (Abd-El-Khalick) was used to get
• students reevaluating their thinking about models.

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Where to go for ideas?

• Ask Pablo does back of the envelope
  calculations regarding environmental issues.
  Often, the replies in the blogs that follow are
  as interesting and show large and small revisions
  to the models. http//askpablo.org/ bottled
  water for instance?
• Several sites give information about the energy
  (embodied, embedded) or CO2 needed to make a
  product, cradle to grave or lifecycle
  analyses of various products.
• Foods http//www.scribd.com/doc/24163/CO2-Emissio
  ns-of-Foods-and-Diets
• Materials http//www.victoria.ac.nz/cbpr/document
  s/pdfs/ee-coefficients.pdf
• Fuel http//www.transportation.anl.gov/pdfs/TA/33
  9.pdf

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Some student models built

• Which is better for the environment
• Driving or flying?
• Shipping fresh produce, canning, or freezing?
• Range fed or feedlot beef?
• Burning or burying garbage?
• Incandescent or fluorescent light bulbs?
• Disposable or cloth diapers?
• Hybrid vehicles or regular gas vehicles?
• Refillable glass bottles, plastic bottles or
  aluminum cans?

17
Another type of question

• How long does it take
• For a new, better mileage car
• For a new, Energy Star appliance
• For new insulation
• For a new, natural gas furnace
• to pay the carbon/energy debt needed to build
  it, in reduced emissions per year?

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Misconceptions

• The goal of this exercise is primarily in
  understanding models, and indirectly theory and
  other NOS concepts. The purpose is NOT to
  understand content.
• The goal of this exercise is also not to get the
  correct answer. The correct answer may not be
  known.
• The purpose is to understand how a system behaves
  and get a reasonable answer.
• If both students and teacher understand the
  above, the experience will go better.

19
Advantages of building their own Excel model.

• The focus is on behavior of the system, there is
  no physical component
• Dispels the misconception that a model must be
  physical
• Increases the focus that a model must act like
  rather than look like its target.
• create explanations and/or models is a 9th
  grade standard. What does this mean?
• Cookbook model?
• Inquiry model?
• We all(?) agree inquiry labs are better than
  cookbook labs, inquiry modeling is likewise
  better than cookbook modeling.

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Advantages of building their own Excel model.

• After the model is built, they test it against
  others who have done similar analyses (either
  other classmates or the web).
• If their model does not work, they reexamine and
  revise and try again, just like a scientists
  would do with a theory. Students showed gain in
  understanding the extent to which and the
  conditions necessary for theory revision.

21
Advantages of building their own Excel model.

• Most importantly, the last step is to form a far
  transfer hypothesis.
• Gas laws can be explained with kinetic molecular
  theory. But, if air is made of little balls in
  random motion
• Hypothesis about diffusion
• Hypothesis about thermal expansion in solids
• Confirmation of these kinds of tests are what
  strengthen theories.

22
Examples of far transfer hypotheses

• After building a flying vs. driving model, use it
  to predict the number of passengers where the
  answer changes.
• After building a coal vs. nuclear electricity
  model, determine what carbon tax (/ton) is
  necessary to force the advantage in favor of
  nuclear.
• After making a predator and prey model, adjust
  it to see how sustainable harvest of deer can
  be calculated by DNR.

23
Other content areas

• Chemistry Kinetics
• Biology Predator prey, Harvey-Weinberg
  Equilibrium
• Geoscience Half-life
• Physics collisions, conservation of energy
  systems, etc. Physics is easy because everything
  is mathematical

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Limitations of the method

• Students need to be able to manipulate equations,
  so some algebra skills (Algebra I?) would be a
  minimum pre-requisite.
• Students need to have some Excel skills. My
  experience was many students get some of this in
  middle and high school, and enough can be taught
  in a day or two.
• On the other hand, opportunity to team-teach with
  math and/or computer science?

25
Further limitation

• Part of my study was looking at a possible
  relationship between students Cognitive Level
  (Piaget concrete vs. formal) and their ability
  to learn from models.
• It is possible that students stuck in the
  concrete level could not make a model.
• Specifically, they could not conceive of a
  variable, and instead used brute force.

26
Further research

• I will be interested in trying this kind of an
  approach in grades 8-12.
• I am seeking collaborators and have ideas for
  many subjects especially chemistry.
• Please contact me lahtiri_at_mnstate.edu if you are
  interested in anything I have said today.
• www.mnstate.edu/lahtiri