Geology 113
Portfolio Project
Guideline 4
4. How do we construct valid scientific arguments in our report?
Your team is being asked to place three types of natural disasters in order
of most to least likely to affect Delaware, and to explain each ranking by
relating evidence you have found to theory for the causes of these events.
Part of the solving the problem is for your team to decide and define what
is meant by "affect Delaware." The criteria for scoring your report define
how your arguments will be judged, so you should think about them while developing
your report. As you are crafting your arguments, it will also help you to
continuously discuss and think about the following things (I have underlined
key phrases that appear in the criteria for scoring the report and presentation):
- You have to figure out what evidence is most relevant and helpful to solving
the problem. What is the evidence for past earthquakes? for past hurricanes?
for past volcanoes? Thinking about the causes and effects of the events
will help you search for relevant evidence. To get started, complete the
diagrams on pages 96 and 110 of the Course Manual. Use the criteria on page
131 of the Course Manual with the criteria application sheets on pages 132-133
to practice evaluating your explanation and the explanations of your teammates.
We will practice examples of these in class to help you get started.
- You can probably accept that sound scientific theories are useful tools
for understanding nature and making predictions. The next important step
is to realize that theories and models have limitations which any argument
developed from them must address. These limitations often come in the form
of anomalous data. One example of anomalous data is that while plate tectonic
theory accounts for why most of the world's major earthquakes occur at plate
boundaries, there have been massive earthquakes far from plate boundaries
- these massive earthquakes seem anomalous according to what plate tectonic
theory would predict and have to be explained. This is an example of connecting
evidence and theory -- finding and explaining the evidence that our theories
handle neatly while not ignoring the anomalous data. When you read your textbook,
attend lectures, and do lab exercises, pay attention to the things that theories
do not explain easily (anomalies), as well as the things that theories seem
to cover quite nicely.<
- There usually are some limitations to the evidence (the data you find on
the web or examine in lab), and your arguments have to address the limitations.
For example, suppose you found a web site that lists every earthquake for
the last 50 years in Delaware, and you discover that there are no major earthquakes
in Delaware over that time span. Can you use this evidence to argue that
there will never be a major earthquake in Delaware? If you consider the possibility
that there might have been a major earthquake in Delaware 51 years ago, you
would be considering the limitations of the evidence (in this case, the limitation
is the time span of the earthquake records). Given this limitation, you would
probably make a slightly different argument. Another example is the lab you
will do on the geologic map of the Newark area. If you do not find any evidence
for volcanoes on this map, can you claim that there will never be an eruption
that will affect Delaware? Would your reasoning be valid? logical? These
are examples of reasoning about the limitations of evidence when using evidence
to help support your scientific arguments. Some of the labs provide you with
experience thinking about the limitations of evidence for scientific arguments.
You can use these as examples to stimulate further critical analysis of the
data you encounter in your research.
While the portfolio project is not designed to turn you into a philosopher
of science, the criteria used to score your work stem from some basic notions
about how scientists construct scientific arguments:
- sound scientific arguments explain the limitations of the theory, the
limitations of the evidence, and the ways that evidence and theory are connected
to one another;
- sound scientific arguments explain the anomalous data -- the rare hurricane,
volcano, or earthquake that occur where theory least predicts.
For these reasons, you should develop your arguments by combining the evidence
you have examined with scientific theory for the causes of these events and
pointing out the limitations of the theories and the evidence. The future
of Newcastle County residents rests upon the quality and soundness of your
arguments.
