Transcript Teaching Geoscience with Data, Models, and Visualizations

Teaching Geoscience with
Data, Models, and
Visualizations
Paul Hoskin
Summer 2007
Exercise:
Sketch a diagram (visualization) of the
following text:
“A supposed equality existing in vertical sections of the earth, whereby the
weight of any column from the surface of the earth to a constant depth is
approximately the same as that of any other column of equal area, the
equilibrium being maintained by plastic flow of material from one part of the
earth to another.” [NASA.gov]
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 A supposed equality
existing in vertical sections
of the earth, whereby the
weight of any column from
the surface of the earth to
a constant depth is
approximately the same as
that of any other column of
equal area, the equilibrium
being maintained by
plastic flow of material
from one part of the earth
to another.
 NASA.gov
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 A state of equilibrium,
resembling flotation, in
which segments of
Earth's crust float (on
liquid mantle material)
at levels determined
by their thickness and
density. Isostatic
equilibrium is attained
by flow of material in
the mantle.
Modeling tool from umich.edu
isu.edu
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 The equilibrium
maintained between
the gravity tending
to depress and the
buoyancy tending to
raise a given
segment of the
lithosphere as it
floats above the
asthenosphere.
mit.edu
Modeling tool from umich.edu
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Visualizations Tell Stories
 Mantle is molten.
 If it is not molten, where does magma come from? How does
the mantle convect?
 Mid-ocean ridges are locations of underwater volcanoes.
 Where do the volcanoes go as the plate moves away from the
ridge?
 Magma is stored in large open chambers in the crust;
flows to fill in open spaces.
 If there are no magma “chambers” how do we create giant
batholiths?
 Students visualize the objects but not the process.
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Flow in the (Fluid?) Mantle
 Conveyor-belt flow model with no sense of time
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How is oceanic lithosphere formed?
 Complete melting beneath ridges
 No labeling of layers
 No temperature or density information
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Magma fills
empty spaces?
Magma intrusions
causing no
metamorphism of
surrounding area
The space problem is
poorly addressed
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What causes confusion?
Metaphors, analogies and models that get
merged with incorrect or incomplete
current and prior understandings?
Ineffective / incomplete graphics?
Poor spatial skills?
All of the above.
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Visualizations improve learning when
they …
 Incorporate learner controlled manipulation of
real or computer simulated models
 Direct the learner to observe effects of changes
in an objects orientation on its 2D image.
 Encourage hypothesis testing about 2D and 3D
objects
 Require externalizing mental images
 Provide practice in mentally rotating an object
 Encourage visualizing the interior of bodies
 Lord, 1985; Ben-Chaim et al, 1988; Duesbury and O’Neil, 1996; Kali and
Orion, 1997
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Thinking about YOUR teaching…
 Simple viewing of visualizations is passive learning
and likely no more effective than passive listening to
a lecture.
 So, what can you as a teacher do about this?
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Let’s look at some descriptions:
Visualization:
– use of images, animations, cartoons, schematics, and blockmodels (e.g., ball-and-stick mineral structures).
Models:
– numerical and/or graphical simulation of a process or
phenomenon.
– an idealization that embodies certain aspects of the “real thing”
that are of interest. (Priscilla Laws, Workshop Physics)
Data:
– information derived from measurement or observation (including
“synthetic” information derived from numerical simulations/models)
[See Manduca & Mogk, 2002, for full discussion].
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Resources to use when preparing
your lectures and labs:
Teaching Geoscience with Visualizations
(http://serc.carleton.edu/NAGTWorkshops/visualization/index.html)
Teaching with Data
(http://serc.carleton.edu/introgeo/teachingwdata/index.html)
How to Use Models
(http://serc.carleton.edu/introgeo/models/HowToUse.html)
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 Learning with Data Workshop (http://lwd.earthednet.org AND
http://earthednet.org/)
 Web-based databases (e.g., NAVDAT: The North
American Volcanic and Intrusive Rock Database:
http://navdat.kgs.ku.edu/)
 A good number of other NSF-funded web-sites
[usually with loose pedagogical descriptions and
good to poor resources for in class use]. An
example:
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Pedagogical Rationale
 99.9% of Earth is inaccessible for direct observation, so
visualizations are essential; temporal and spatial scales
cannot easily be simulated in the lab, so visualizations
are essential.
 Data-enhanced learning experiences, including activities
in which students collect and interpret their own data
AND in which they explore research databases to
answer questions, are important tools for their learning.
 In short:
– using data improves learning about science
– using data fosters inquiry and active learning
– can easily tailor lectures/labs to be relevant and meaningful (e.g.,
global warming, Mars mineralogy, seismic hazards; see lead articles
of EOS)
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Example: teaching with a model
 Darcy’s Law: development of a numerical model
 Set-up: in-lecture discussion may be proceeded
by a demonstration where students are asked to
make predictions prior to observing a physical
model operate.
 Aim: to gently lead a math-phobic class to
formulate (and later test/verify) Darcy’s Law.
 Method: using the black-box approach
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Step 1a: describe a “real world” scenario
Step 1b: sketch a physical model and label
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Step 2: identity where the black-boxes go
and start to describe (hint: in this case it is useful to
have the class identity the units of the output black-box [flow rate
volume per unit time])
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Step 3: flesh it out into a real math-looking
formula.
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Step 4: do “mind experiments” to have the
class make predictions using the formula
for testing in an associate laboratory.
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The Advantages of Models
Is interactive
Can introduce specific content and
terminology
Can be used to explore “what if” scenarios
Can be used to explore the sensitivity of a
system to value changes of specific
variables.
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Thinking about YOUR teaching…
 As a teacher (1) what would you have done to teach that
example better; (2) what two specific examples relevant
to your sub-discipline could you use in a lecture?
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Example: teaching with data
 The modern CO2 record
(a shortened and refocused example modified from:
http://serc.carleton.edu/introgeo/teachingwdata/examples/ModernCO2.html)
 For in-lecture use (e.g., a freshman-level physical
geology lecture).
 The exercise would follow a discussion on what the class
already know about greenhouse gases and global
warming.
 Aim: (i) to become familiar with atmospheric CO2
fluctuations at Mauna Loa, Hawai’i; (ii) to understand
what processes might explain the long-term trend in
atmos. CO2 conentration; (iii) to get a feeling for data
“quality” and predictions based on such data.
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Step 1: student groups are given selected
data to plot (specific instructions are given
on the axis labels, intervals, and limits)
Step 2: students are asked to describe
their plots and make two observations;
these are discussed as a class
Step 3: the whole dataset is pieced
together step-by-step
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 Step 4: the class is given a copy of the plot and again asked to
make two observations. The observations are discussed.
 Step 5: the class is told that once the 460 ppmw CO2 threshold is
crossed, the Earth will experience regular catastrophic weather
changes and will have passed the point of no return. They are
instructed to draw a line of best-fit through the data and (i) calculate
the rate of CO2 accumulation per year over the period of 1975 to
2000; (ii) estimate when we will reach the 460 ppmw threshold. Two
things can then be discussed: how to draw a line of best-fit and if
such an approach is valid, and what the range of estimates means
(there will be a range of estimates).
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Thinking about YOUR teaching…
 (i) Do you think such an exercise is useful and if so, what will you do to
make sure that all class members are engaged and contributing? (ii) What
dataset might you use in a lower-division class? Upper-division class?
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Acknowledgements
Michelle Hall-Wallace, Uni. Arizona
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