DQC Workshop
Detroit Airport Westin - November 20, 2010
Wright Room, Westin Hotel
Overall Goals of the DQC Project
• Diagnose how students use or don’t use key
principles (tracing matter and energy) to reason
about biological phenomena .
• Explore how teaching strategies may improve
principle-based reasoning by college-biology
students.
History of the DQC Collaborations
• MSU researchers formed a group to look at college-student (MSU)
understanding of key principles related to matter, energy, and
information.
• CCLI Phase 1 grant (years?)– faculty development combined with
science education research, three years worth of annual workshops
at Ecological Society of America annual meeting, data collected
from students at 15 institutions, BioScience paper from the large
data-set, lots of more specific posters based on parts of the data-set
and several papers in preparation by faculty participants
• CCLI Phase I grant (years?) - faculty development combined with
science education research, two annual meetings, most faculty
involved teach Introducory Biology, DQCs expanded and
repackaged to target cellular/molecular through ecosystem level.
Conceptions about carbon transforming
processes
• List as many student alternate or
misconceptions about carbon transforming
processes (e.g. Ps, Rsp) as you can in 3
minutes.
• Group those conceptions depending on whether
they are related to tracing matter, tracing energy,
or choosing appropriate scales at which to
reason.
Research Goal: Connect conceptions to principlebased reasoning
We investigated college students’ ability
to apply the principles of conservation of
matter and energy across scales when
reasoning about biological processes that
generate, transform, and oxidize organic
carbon molecules.
Summary of 08-09 Findings
Methods
• Pre- and post-DQCs to 495 students at 12 institutions
• In between the pre and post-tests, faculty used active teaching
strategies that targeted principled reasoning about matter and
energy
• Faculty coded their own students’ responses. We regrouped
responses. Codes were “scientific”, “mixed”, “informal”, or “no
data”
• Looked for quantitative trends (pre-post gains, differences in
difficulty among processes, principles, and scales)
• Looked for qualitative trends
Key Findings
• Some students applied
principle-based
reasoning (9% in pretests and 24% in posttests).
• Some applied informal
reasoning (20% in pretests and 15% in posttests).
• Most (62% in pre-tests
and 55% in post-tests)
applied mixed reasoning.
Characteristics of answers in each group
• Principle-based reasoning
– Able to trace matter and energy across scales
– Don’t confound matter and energy or think either than disappear
– Can account for individual atoms and molecules as they are rearranged
• Mixed reasoning
–
–
–
–
–
Awareness of “invisible” processes, but insufficient knowledge to describe them
Confound matter and energy
Oversimplify laws of conservation
Use informal language in part, but not all of answer
Prolific use of school science terminology
• Informal reasoning
– Make no attempt to trace matter or energy
– Rely heavily on informal language or inappropriate analogies
Key Qualitative Findings
1. Students confound energy and matter and
use of energy as a “fudge factor”
2. Reasoning across scales is hampered by
a lack of understanding of atoms and
molecules
Use of Energy as a “Fudge Factor”
• Students often chose distracters that indicated that they thought
energy could become matter and matter could become energy.
• Students often chose distracters that included energy disappearing,
being “used up” or being “burned up”.
–
–
Indicates that they are drawn to words used in informal discourse
Indicates that they are drawing inappropriately narrow boundaries around systems which is a
problem related to scale. Once energy leaves the boundaries, students no longer feel the
need to account for it.
• Use of energy as a “fudge factor” was more common when students
were asked to reason at the atomic-molecular level
Findings: Energy as a “Fudge Factor”
A loaf of bread was left uncovered for
two weeks. Three different kinds of mold
grew on it. Assuming that the bread did
not dry out, which of the following is a
reasonable prediction of the weight of
the bread and mold together?
A) The mass has increased, because
the mold has grown.
B) The mass remains the same as the
mold converts bread into biomass.
C) The mass decreases as the growing
mold converts bread into energy. 11%
D) The mass decreases as the mold
converts bread into biomass and
gases.
A potato is left outside and gradually
decays. One of the main substances in the
potato is the starch amylose ((C6H10O5)n).
What happens to the atoms in amylose
molecules as the potato decays? Choose
True (T) or False (F) for each option.
T F Some of the atoms are converted into
nitrogen and phosphorous: soil nutrients.
T F Some of the atoms are consumed and
used up by decomposers. 88%
T F Some of the atoms are incorporated
into carbon dioxide.
T F Some of the atoms are converted into
energy by decomposers. 85%
Findings: Energy as a Fudge Factor
• For questions that explored matter-energy
conversions
– 21% of students chose the distracter in a
multiple-choice question
– 56% of students chose the distracter in a
multiple T/F questions
Findings: Energy as a Fudge Factor
• Students commonly ignore the energetic costs of transformation
of matter and energy in trophic web.
•
•
•
When asked “Of the energy gained by a plant (i.e. producer), what
percentage is typically transferred to a rabbit that eats the plant?”, 65% of
students thought more than 20% of the energy gained by a plant would be
transferred to the herbivore that consumes it.
When asked about energy transfer through a food web, only 47% of students
thought the top of a food web would have “less available energy than the
trophic levels below it”.
When asked about decomposition, 28% of students thought the mass of mold
and the bread upon which it is growing would stay the same as the mold
grows.
Key Qualitative Findings
1. Students confound energy and matter and
use of energy as a “fudge factor”
2. Reasoning across scales is hampered by
a lack of understanding of atoms and
molecules
Students lack an understanding of
atoms and molecules
• Without an understanding of the particulate nature of matter,
students cannot trace matter and energy across scales. They
are limited to reasoning only at the macroscopic level.
• Students think molecules are equivalent in terms of the
energy they contain.
• Students think atoms can be converted to other atoms or they
don’t use this as a constraining idea.
• Students see overly simplified gas-gas and solid-solid cycles
as a result of being uncomfortable with atoms and molecules.
Students lack an understanding of
atoms and molecules
A potato is left outside and gradually decays. One of the main substances in the
potato is the starch amylose ((C6H10O5)n). What happens to the atoms in amylose
molecules as the potato decays? Choose True (T) or False (F) for each option.
T F Some of the atoms are converted into nitrogen and phosphorous: soil nutrients.
277T, 165F
T F Some of the atoms are consumed and used up by decomposers.
274T, 167F
T F Some of the atoms are incorporated into carbon dioxide.
315T, 122F
T F Some of the atoms are converted into energy by decomposers.
154T, 287F
T F Some of the atoms are incorporated into water.
228T, 212F
Discussion
• We saw some learning gains, but the majority of students
were still using “mixed” reasoning even after instruction.
• Why do you think this is?
• What do you think we can do about it?
Conclusions
•
Principled reasoning is difficult for students most likely because
–
–
•
They lack the necessary understanding of atoms and molecules.
They reason about mega or micro-scale phenomena by inappopriately applying cultural models
or their own embodied experiences, both of which are situated in the macroscopic world.
Theories about language and informal reasoning may be useful in interpreting
why students have difficulty moving from informal to scientific discourse.
Students look for “actors” that drive processes. They have trouble thinking of
atoms, molecules, and cells as actors. When they think about organisms as
actors, they are precluded from thinking about the components/cells within the
actors, making it hard to move across scales.
Conclusions
•
•
Science instructors at multiple levels and in multiple domains need to help
students see the necessity of principled reasoning and how their cultural
models interfere with principled reasoning and to alter their course-taking
practices.
This doesn’t mean that we can forgo the details. Instructors need to give
students to tools that enable them to connect the details of course content
and student responses to the principles behind them.
Summary of 09-10 Data
Generated
Data Generated by Your Students
DQC
# Pre (# classes)
# Post (# classes)
Photosynthesis A
49 (2)
45 (1)
Photosynthesis B
33 (1)
47 (2)
Respiration A
403 (3)
221 (4)
Respiration B
117 (2)
439 (4)
Biosynthesis A & B
None
None
Energy Pyramid
49 (1)
None
Rainforest
132 (1)
182 (2)
Biofuels
40 (1)
38 (1)
Grandma Johnson
161 (2)
163 (2)
Keeling Curve
59 (2)
52 (2)
Preliminary Findings From the 2009-2010 Data
•
Not sure what to put here
Where we go from here
Next Steps
• A “methods” paper is in progress.
• Work toward further validation of the items (IRT analysis,
interviewing students)
• Tie college-level data to K-12 data on learning
progressions.
• Continue to support “spin-off” and “follow-up” research
conducted by faculty participants.
• Continue to explore efficacy of teaching strategies
• Development of DQCs for evolution and biodiversity.