The Case Study Method for the Assessment
of Student Learning: Using Scientific
Reasoning and Deep Geological Time to
Predict Future Environmental Impacts
Chen Zhu
Geological Sciences and School of Public and
Environmental Affairs
Brooke A. Treadwell
Educational Leadership and Policy Studies
Acknowledgements
 Departmental colleagues, Simon Brassell, Claudia Johnson,
Michael Hamburger, Jim Brophy, Bruce Douglas for sharing
interests and discussions
 Lilly Freshmen Learning Project leaders Joan Middendorf,
David Pace, and Simon Brassell and “cohorts”
 Collaborators for this research project: George Rehrey and
Claudia Johnson
The Teaching and Learning Problem
 Often, the immensity of deep geological time (DGT) is
very difficult for non-science majors to understand and to
use when applying it to geological problems
 DGT can be both a bottleneck and a threshold concept for
many science classes
 DGT is important for student success within Geology and
other sciences (Hawkins 1978)
 Prepare scientifically literate, informed citizens to vote in
elections that will impact environmental policy on highstakes issues such as climate change/the carbon tax and
nuclear waste disposal.
Dinosaur
extinction
65 mya
The 4.6 billion-year history of Earth
 We are now in Holocene
Epoch (11,500 years before
present to the present)
 Holocene is an interglacial
period
 Pleistocene “most recent in
Greek” (11,500 - 2.5 million
years before present)
 Last glacial maximum 25,000
years ago
Review of Literature
Preconceptions inhibit students from achieving an
adequate understanding of DGT


Numerical difficulties:
• Millions vs. billions (Trend 2000)
• Dinosaurs died before life began (Libarkin 2007)
Confusion about basic science
• Lunar phases (Schoon & Boone 1998)
• Reasons for seasonal change (DeLaughter & Stein 1998)
• Global warming is due to destruction of Ozone layer
DeLaughter, J. E. and S. Stein (1998). "Preconceptions about earth science among
students in an introductory course." EOS 79: 429-432.
Review of Literature
 Elementary School
Ault, C. R. (1982). "Time in geological explanations as perceived by
elementary school students." Journal of Geological Education 30: 304-309.
 High School
 Hidalgo, A. J. and J. Otero (2004). "An analysis of the understanding of
geological time by students at secondary and post-secondary level."
International Journal of Science Education 26(7): 845-857.
 Dodick, J. and N. Orion (2003). "Measuring student understanding of
geological time." Science Education 87(5): 708-731.
 College
 Libarkin, J. C., J. P. Kurdziel, et al. (2007). "College student conceptions
of geological time and the disconnect between ordering and scale." Journal
of Geoscience Education 55(5): 413-422.
 Catley, K. M. and L. R. Novick (2009). "Digging deep: Exploring college
students' knowledge of macroevoluntionary time." Journal of Research in
Science Teaching 46(3): 311-332.

Review of Literature – Suggested Learning Activities
 Visualize magnitude by analogy or metaphor-based activities

(Pyle 2007).
 Equate geologic time to physical distance

(Richardson 2000, Hemler & Repine 2002)
 Translate DGT into a familiar time span (one calendar year)

(Everitt, Good & Pankiewicz 1996, Nieto-Obregon 2001).
 Create personal metaphor

(Ritger & Cummins 1991).
All these activities presuppose that once students compare
the geological time scale to a familiar distance, volume,
mass or time period, they will be more likely to grasp the
brevity of humans’ existence on Earth relative to the
enormity of DGT.
Geologic Time Metaphors
Geologic Time Metaphors
Situational Factors
 Environmental Geology G171 for non-science majors
 Possibly a gateway course
 37 undergraduates in 2009
 73% of students - First college science course
 49% of students - Self reported knowing “almost
nothing” about DGT
 Only 8% indicated being highly confident in their
understanding of DGT
Introductory Geology Courses
G103
Earth Science: Materials and
Processes
Brophy/Dunning
Fall/Spring
G104
Evolution of the Earth
Brassell/Millen
Fall/Spring
G105
Earth, Our Habitable Planet
Pratt/Douglas
Fall/Spring
G111
Physical Geology
Brophy
Fall
G112
Historical Geology
Polly
Spring
G114
Dinosaurs and Their Relatives
Johnson
Fall
G116
Our Planet and Its Future
Dunning
Fall/Spring
G171
Environmental Geology
Zhu/Douglas
Fall/Spring
Why is DGT a bottleneck?
Quantitative skills:
• Large numbers, abstract numbers
• Proportions and scales
 Lack of scientific background and literacy
 Relation between geological time scale and
something real (dinosaurs died a long, long
time ago, 65 mya)

The Research Questions
 Can participation in distance-metaphor building
activities help students visualize the immensity
of DGT?
 Does learning DGT help students acquire better
scientific reasoning skills?
 To what extent does the case study method
enable students to understand and apply the
concept of DGT to problem-solving?
Background to Project
Decoding Discipline Model and the
Freshman Learning Project

Where do most students get stuck?
– Pace, D and Middendorf, J. 2004. Decoding the
disciplines: Helping students learn disciplinary ways
of thinking. New Directions for Teaching and
Learning Summer, no. 98.
– Pace, D and Middendorf J. 2007. Easing entry into the
Scholarship of Teaching and Learning through
focused assessments: The decoding the disciplines
approach. In To Improve Academy, (Bolton: Anker
Publishing).
How this study is different
 Innovation: (a) a real world environmental problem
with the need of understanding geological time scale
that students can relate to and engage with;
(b) future vs. past; (c) apply/outcome driven
 Scaffold learning - based upon Anderson’s Revised
Taxonomy of Educational Objectives
Cognitive Process
Understand > Apply >
Analyze
Learning
Opportunities
Readings
3 - Lectures
Class activities
Homework #2
Case-Study in final exam
2 Labs
Anderson, Lorin W., David R. Krathwohl, and Benjamin Samuel Bloom. A Taxonomy for Learning, Teaching,
and Assessing : A Revision of Bloom's Taxonomy of Educational Objectives. Abridged ed. New York:
Longman 2001.
Geological Repository for Highlevel Nuclear Wastes
Yucca Mountain
Nevada
Nevada Test Site
Las Vegas
Into the realm of geological time
scale
July 9, 2004, the U.S. Court of Appeals
of the District of Columbia vacated
Environmental Protection Agency’s
10,000-year period for compliance
Now to 1 million years or “within the
period of geologic stability”
In the next million years …
All of these orbital changes influence the amount of sunlight hitting the Earth.
The recurrence of ice ages is roughly on 100,000 and 40,000 time scales
Milankovitch cycle
How this study is different
 Personal engagement
 Nuclear waste example; requires society’s decision and has
an outcome students may care about;
 Case Study: local coal burning power plant (part of the
final exam);
 Lab requires students to create a visual product
representing geological time and apply it to the
nuclear waste and global warming problems;
 Authentic Assessment – Students are asked to do the
“type of thinking” and tasks that the expert in that
field would do.
Wiggins, Grant P. 1998. Educative assessment: Designing assessments to inform and improve student performance. San Francisco,
Calif.: Jossey-Bass.
Lab – Part I
Mark the following events on the toilet paper, each sheet = 20 million years
Sheets
Geological time
0.0005
10,000
0.75
15,000,000
3.25
65,000,000
9.00
180,000,000
14.00
280,000,000
18.5
363,000,000
28.5
570,000,000
170
3,400,000,000
190
3,800,000,000
230
4,600,000,000
Events
Age of human
Formation of Himalayan Mountains
Dinosaurs became extinct
Early birds and mammals
Dinosaurs appear, final assembly of Pangaea
Early trees, formation of coal deposits
Beginning of Cambrian period, rise of multi-cellular animals
Earliest life-forms (single-celled bacterial)
Oldest known Earth rocks
Origin of Earth
Lab – Part II
Using the
perforations
between sheets as
a ruler, mark the
names of items as
listed in the table
below. You will
have to calculate
the number of
sheets required to
complete each
step in the table
below. Each
sheet of the
paper towel is
equal to 10,000
years
Step #
Time
Events
1
~ 781,000 BP
last magnetic pole reversal
2
~126,000 BP
base of Eemian interglacial phase
3
~100,000 BP
Neanderthal man
4
50,000 BP
First Homo sapiens
5
15,000 BP
The last glacial maximum
6
13,000 BP
Humans first inhabit North America
7
10,000 BP
End of last Ice Age, Modern man
8
8,000 BP
Founding of Jericho, the first known city
9
~6000 BP
Human written records
10
2,000 BP
Roman domination of the world
11
500 BP
12
~ 450 BP
~220 BP
scientific revolution
Industrial revolution began
15
~150 BP
~ 40 BP
16
0
17
2 AP
13
14
European rediscovery of the Americas
First President of United States
Humans first explore the moon
Now
Congressional election, 2010
32 AP
Known crude oil reserves are used up (these numbers are highly
contested. This number comes from Wikipedia as of November 14, 2006)
72 AP
Known natural gas reserves are used up (these numbers are highly contested. This number
comes from Wikipedia as of November 14, 2006)
~96 AP
Global warming effects set in and global mean temperature increase 2 -4 oC. Sea level rises
~100 AP
The birth of your 5th generation offspring.
252 AP
Known coal reserves are used up (these numbers are highly contested. This number comes
from Wikipedia as of November 14, 2006)
19
290 AP
The 100th Olympic game
20
328 AP
The 100th FIFA World Cup
21
~ 4000 AP
The 1000th President of the United States
22
~4800 AP
5000th anniversary of the foundation of the United States
18
~25,000 AP
Your 1000th great grandchildren
23
~50,000 AP
24
Next ice age
1,000,000 AP
25
Safety of the Yucca Mountain repository
Follow up Homework
 Given your knowledge of the geological time
scale and human history, what seems like a
reasonable and feasible time period for the nuclear
waste to be stored safely at the Yucca Mountain
geological repository? Would 10,000 years be
enough? 100,000 years? 1,000,000 years? Why?
Be sure to support your answer by using
geological numbers and the time scale of events
that you identified in the lab. This answer should
be about 4-5 sentences long.
Follow-up Homework
Write an essay in which you either agree or disagree
with the following statement: “We are in the warm
period of the glacial and inter-glacial cycle, and are
surely heading toward the next glacial period.
Therefore, global warming is a good thing because it
will delay the coming of the next ice age.”
Class Activities
Pre-course knowledge survey at first class
II. Lectures and class discussion about DGT
III. Distance-metaphor building lab
IV. Post lab survey/homework/essay
V. Post-course knowledge survey at last class
VI. Final take home exam using case study method
I.
Evidence of Student Learning
 Pre and Post-Knowledge Survey
 Post lab survey
 Final Exam – Case Study
Knowledge Survey
 Measure students’ perceptions of their
ability to solve problems, not their actual
ability.
 Nuhfer and Knipp (2003) found that very
few students display gross overconfidence
when self reporting. They concluded that
such “aberrations contributed by
occasional individuals never affect a class
average in a significant way” (p. 66).
 We averaged student scores to draw
conclusions about improved DGT
understanding and application.
Nuhfer, E. and D. Knipp (2003). "The Knowledge
Survey: A Tool for All Reasons." To Improve the
Academy 21: 59-78.
Knowledge Survey
Selected Questions
 Explain the Geological Time Scale & why it is important to Environmental
Geology
 Describe the age of the earth in geological time and how we know it is an
accurate estimation
 Estimate the number of years we should guarantee buried high level nuclear
waste will be safe at Yucca Mountain. Explain why.
 Estimate how far back we need to look into the geological past to determine if
human activity is causing climate change. Describe why this is significant.
Scale: How confident are you that you could answer this question on a graded test:
 1 – Not confident
 3 – Somewhat confident
 5 – Very confident
Presurvey
Postsurvey
Change
Pre and Post-Knowledge Survey Results
Explain the Geological Time Scale and why it is important to Environmental Geology
2.27
4.26
1.99
Explain the time frame for determining the possible adverse effects of global warming (tens,
hundreds, thousands, millions of years)
2.38
4.39
2.01
Describe the time frame for the cycle of glacial and interglacial periods (approximately tens,
hundreds, thousands, millions of years)
1.86
3.91
2.05
1.19
3.87
2.68
2.62
4.22
1.60
Identify how far back we need to look into the geological past to determine if human activity is
causing climate change. Explain why this is significant.
2.38
4.00
1.62
Explain how scientists predict the future safety of nuclear waste disposal and what factors they
must consider
2.19
3.78
1.59
Total Average Score
2.13
4.06
1.93
Survey Test Question
Identify the Milankovich cycles and explain why they are important to Environmental Geology
Describe the age of the earth in geological time and how we know it is an accurate estimation
Strongly
Agree
Agree
Strongly
Disagree
Post Lab Survey
The lab helped me understand Geological Time
1
2
3
4
5
The lab helped me visualize the immensity of the Geological Time
Scale
1
2
3
4
5
The lab helped me relate geological time to current real world issues and
the search for solutions
1
2
3
4
5
The lab helped me answer the homework question about burying nuclear
waste at Yucca mountain
1
2
3
4
5
The lab helped me answer the homework question about human activity
and global warming
1
2
3
4
5
The lab help me understand the time frame for the cycle of glacial and
interglacial periods
1
2
3
4
5
The lab helped me see the relationship between the current geological
era we are living in and the Geological Time Scale
1
2
3
4
5
Post Lab Survey Results
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Understand DGT
Visualize DGT
Ratings: 1 = strongly disagree
5 = strongly agree
Relate DGT to world issues
Understand glacial/
interglacial periods
Relate current era to DGT
Case Study
 You just joined a student environmental group. Write the
text of a presentation you will give to IU student government
defending the belief that anthropogenic activities are a
contributor to global warming, and hence an important
reason why IU should retire its coal fired power plant. Your
presentation should:




Explain the immensity of geological time, variations in CO2
concentrations and glacial & inter-glacial cycles within the
Quaternary
Use scientific reasoning (observations, theory, experiments,
evidence & facts) to show that the CO2 increase is likely beyond
natural variability
Use graphs to support your argument
Identify 2 other contemporary environmental issues which require
an understanding of the geological time scale. Explain how.
Case Study Rubric
Criteria
 Description of the immensity of DGT
 Use of DGT to describe the link between the CO2 rise & global
warming to human activity
 Use of DGT to argue that global warming won't inhibit next ice
age
 Explanation of how DGT is key to understanding other
environmental issues (excluding global warming)
Scores
 3 – accurate answer, clear & detailed
 2 – accurate answer, some detail
 1 – vague/unclear/answer indicated misunderstanding
Case Study Results
65%
Met 1 or more criteria, demonstrating at least a
basic understanding of DGT
56%
Demonstrated the ability to use scientific
reasoning
Met 2 or more criteria, demonstrating a solid
understanding of DGT
Met all 4 criteria, demonstrating an excellent
understanding of DGT
Met and exceeded all 4 criteria, demonstrating an
exceptional understanding of DGT
45%
17.5%
7.5%
Conclusions
 Students perceived the distance-metaphor activities as
enabling them to visualize the immensity of DGT
 Large increase in students’ confidence in their ability
to engage in scientific reasoning using DGT
 The majority of students demonstrated the ability to
use DGT to engage in scientific reasoning
 The majority of students applied the concept of DGT
to problem-solve within case-study assignments
Next Steps
Adjustments to the course
 This Fall we added an additional metaphor building
activity to the lab, asking students to create their own
visual depiction of the immensity of DGT, after they have
worked in teams using the toilet paper exercise to
visualize its immensity.
Further Research
 Larger sample size
 Examine students’ ability to transfer problem solving
skills to a different discipline, course, or problem set
Thank you
Case Study Results
65%
Met 1 or more criteria, demonstrating at least a
basic understanding of DGT
45%
Met 2 or more criteria, demonstrating a solid
understanding of DGT
Met all 4 criteria, demonstrating an excellent
understanding of DGT
Met and exceeded all 4 criteria, demonstrating an
exceptional understanding of DGT
17.5%
7.5%
56%
Demonstrated the ability to use scientific
reasoning
Sources









Ault, C. R. (1982). "Time in geological explanations as perceived by elementary school students."
Journal of Geological Education 30: 304-309.
Catley, K. M. and L. R. Novick (2009). "Digging deep: Exploring college students' knowledge of
macroevoluntionary time." Journal of Research in Science Teaching 46(3): 311-332.
DeLaughter, J. E. and S. Stein (1998). "Preconceptions about earth science among students in an
introductory course." EOS 79: 429-432.
Dodick, J. and N. Orion (2003). "Measuring student understanding of geological time." Science
Education 87(5): 708-731.
Everitt, C. L., S. C. Good, P. R. Pankiewicz (1996). "Conceptualizing the inconceivable by depicting
the magnitude of geological time with a yearly planning calendar." Journal of Geoscience Education
44: 290-293.
Fink, L. Dee (2003). Creating significant learning experiences: An integrated approach to designing
college courses. San Francisco, Calif.: Jossey-Bass.
Hawkins, D. (1978). "Critical barriers to science learning." Outlook 29: 3-23.
Hemler, D. and T. Repine (2002). "Reconstructing the geologic timeline." The Science Teacher 69(4):
32-35.
Hidalgo, A. J. and J. Otero (2004). "An analysis of the understanding of geological time by students at
secondary and post-secondary level." International Journal of Science Education 26(7): 845-857.
Sources












Libarkin, J. C., J. P. Kurdziel, et al. (2007). "College student conceptions of geological time and the disconnect
between ordering and scale." Journal of Geoscience Education 55(5): 413-422.
Nieto-Obregon, J. (2001). "Geologic time scales, maps, and the chronoscalimeter." Journal of Geoscience
Education 49(1): 25-29.
Novak, J. D. (1988). "Learning science and the science of learning." Studies in Science Education 15: 77-101.
Nuhfer, E. and D. Knipp (2003). "The Knowledge Survey: A Tool for All Reasons." To Improve the Academy
21: 59-78.
Pace, D and J Middendorf (2004). Decoding the disciplines: Helping students learn disciplinary ways of
thinking. New Directions for Teaching and Learning Summer, no. 98.
Pyle, C. (2007). "Teaching the time: Physical geography in four dimensions." Teaching Geography 32(3): 121123.
Richardson, R. M. (2000). "Geologic time (clothes) line." Journal of Geoscience Education 48: 584.
Ritger, S. D. and R. H. Cummins (1991). "Using student-created metaphors to comprehend geologic time."
Journal of Geological Education 39: 9-11.
Schoon, K. J. (1992). "Students' alternative conceptions of Earth and space." Journal of Geological Education
40: 209-214.
Schoon, K. J. and W. J. Boone (1998). "Self-efficacy and alternative conceptions of science preservice
elementary teachers." Science Education 82(5): 553-568.
Trend, R. D. (2000). "Conceptions of geological time among primary teacher trainees, with reference to their
engagement with geoscience, history, and science." International Journal of Science Education 22(5): 539-555.
Wiggins, Grant P. (1998). Educative assessment: Designing assessments to inform and improve student
performance. San Francisco, Calif.: Jossey-Bass
Atmospheric CO2 in the past
Yucca Mt. – Potential Repository
 Desert climate (170 mm/yr vs. Bloomington ~1200
mm/yr);
 On federal land;
 Away from large population centers;
 Nevada has only two congress men (and two
senators);
 30 years study and 30 billion dollars.
Infiltration rate
At present, evaporation exceeds
precipitation (170 mm/yr) - hypothesis;
Water drips down in tunnel – reality
check;
When is the next ice age?
Recharge, mm/yr
Estimated Recharge for Yucca Mountain
(Zhu et al. Water Resources Research , 2003)
20
15
10
15±5 mm/yr
5
5±1 mm/yr
0
Holocene
Late Pleistocene
U.S. Nuclear Regulatory Commission:
Next 10 ky
13-64 mm/yr 10 ky - 1 ma