Activity 2: Writing Assignment

Activity 2: Critically Reading Scientific Literature and the Scientific Method

Directions

Do comets still deliver substantial water to Earth? Could the oceans be growing year by year? Frank et al. (1986) think so. What is their evidence and how was it received by the scientific "establishment?" We will give you some experience in critical evaluation of hypotheses and data using a real-world example with great relevance to our topic. Their paper was, understandably, controversial, so there has been much discussion and evaluation of the data and conclusions. It's a great example of how the scientists vet their ideas through publication and receive feedback from their (not always kind) colleagues. It is also an opportunity to explore the "scientific method" a bit.

1. Read: Frank, L.A., Sigwarth, J.B., and Craven, J.D., 1986. On the influx of small comets into the Earth' s upper atmosphere. II Geophysical Research Letters, v. 13, p. 307-310.
   The full set of papers and discussion are available here
   This is a fascinating paper (we have assigned just the one short paper that outlines the authors' "interpretation" of the small-comet impact data with implications for the mass balance of water on Earth; you can also read the companion data paper, available on the Web site above, for more details).
2. Search the Web for news articles and evaluations of the hypothesis.
   For example, you could go to that same Web site (Small Comets) to see what they are saying now in their defense—how they summarize the impacts (excuse the pun) of their earlier work. You can (and should!) also download pdfs of all of the comments and replies that they received (critical evaluations!) after their article was published in this respectable peer-reviewed journal. Yes, even peer review does not guarantee that the data and interpretations are without issue.
3. After reading the article, the comments/replies, and any other resources you found that are helpful, write a summary (1000 words or less—be succinct) of your thinking on this issue as informed by the discussions in the literature by scientists. Use the following outline:
   • Briefly summarize the authors' original hypothesis (were there multiple-working hypotheses?).
   • Outline the data in their paper that initially supported or refuted their hypothesis (in the scientific method one cannot "prove" an hypothesis, only disprove one).
   • Summarize the authors' conclusions regarding the implications of their data.
     • Has the hypotheses been refuted based on subsequent analysis of the data or methodology (by others)?
     • What are the major issues that present obstacles to general acceptance of the idea that comets continue to steadily supply substantial water to Earth's atmosphere (and oceans).
   • Summarize your own reactions to the original hypothesis and bring in any data or concepts that you find compelling one way or the other.
   • Provide your sources: References cited
4. Save your paper as either a Microsoft Word or PDF file in the following format:
   
   L1_Activity2_AccessAccountID_LastName.doc (or .pdf)
   
   For example, student Elvis Aaron Presley's file would be named "L1_Activity2_eap1_presley.doc"—this naming convention is important, as it will help me make sure I match each submission up with the right student!

If you'd like to discuss this activity and/or ask questions to the class, use the Questions discussion board on Canvas.