Sunday, May 24, 2009

Paradigms, Puzzles, and Citizen Science in Schools

A month or so ago I finally got around to reading Thomas Kuhn's classic, The Structure of Scientific Revolutions. I say "finally" because the book was first published in 1962, while I was still in junior high school. The book was--and still is-- widely read and referenced. As an indicator of the book's impact, consider that the term "paradigm shift" came into common usage through this book.

The Structure of Scientific Revolutions (I am going to call it TSSR) is engaging--the best book I have read in quite a while--though not an easy read. Kuhn refers to it as an "essay." The term is apt, because TSSR is a closely reasoned argument for what was, in 1962, a new view of science.

It's worth spending a moment to summarize the old view and the new one that Kuhn sets forth in TSSR because, despite TSSR, the old view is still alive and well in science education. The contrast of views also raises interesting questions about what we should be doing in science education and about how citizen science might fit into that program.

The Old View

Kuhn was a science historian, which is why a key question in TSSR is how we should understand scientific progress. Kuhn describes the traditional, pre-TSSR view of scientific progress as follows: (All quotations are from the paperback, third edition of TSSR. I also note that Kuhn only refers to all scientists as men ... sigh ... that was then.)

If science is the constellation of facts, theories, and methods collected in current texts, then scientists are the men who, successfully or not, have striven to contribute one or another element to that particular constellation. Scientific development becomes the piecemeal process by which these items have been added, singly and in combinations, to the ever growing stockpile that constitutes scientific technique and knowledge. (p. 1)

The key image here is the constantly growing stockpile of knowledge. In this traditional view, the story of science is one of incremental accumulation in which, as each decade and century passes, we are a little closer to complete understanding.

The work of science education, given this view, would be to introduce students to the knowledge in that pile. Kuhn's use of the word "constellation" acknowledges that the stockpile is structured. The word "edifice" is sometimes used to describe this view of science: it is a large, complex building constructed brick by brick since the time of Aristotle. Science education should then be about introducing students to the structure and content at the foundation level.

This view of science matches pretty closely with what students tell us when we survey them about the nature of science. It is a pile of facts about the world acquired through a process called the scientific method.

Kuhn's View: Paradigms

TSSR argues that this picture of science is not supported by historical fact. Kuhn makes this argument by looking at examples. The transition from the Ptolemaic, earth centered view of the universe to the Copernican view did not add another brick to the edifice of science; instead it completely rearranged the bricks. Similarly, the movement from a phlogiston theory of combustion to Lavoisier's oxygen theory was a complete turn around in thinking about what happens when something burns. Or, to take another example, the quantum view of light as electromagnetic radiation completely displaced wave theory and a belief that there must be something called "ether" to support the propagation of light waves.

Kuhn recognizes that these upheavals, as important as they are, are the exception rather than the rule. He distinguishes between "normal science" and the much more unusual condition of science in a time of revolution. Normal science is where most of the day-to-day work of science gets done. It is where the steady, cumulative work happens.

So, you have normal science working away for hundreds of years, piling up observations, most of which fit with the theories in place at that time, but including a few that don't fit. When the things that don't fit are numerous or important enough, the normal scientific work enters a time of crisis, followed by a revolution. Then normal scientific work returns. The revolution in thinking about geology in the 1950s and 1960s, from a geosyncline theory of movement of the earth's crust to plate tectonics, is a recent example of such a revolution followed by a return to productive, normal science.

Kuhn asks whether the scientists working before such a revolution--say, on the phlogiston theory of combustion--were somehow any less "scientific" in their work. Take, for example, Joseph Priestley, one of the people credited with discovering oxygen. He went to his grave defending phlogiston theory, despite his discovery. Does that make him less a scientist? Was his application of "the scientific method" somehow less complete than Lavoisier's?

Of course not. The point is that there is more than "scientific method" that binds normal scientific work together in any discipline at any point in time. Kuhn calls the collection of values, beliefs, methods, shared examples, and shared problems a "paradigm." What separated Priestley and Lavoisier was immersion in two different paradigms.

The word "paradigm" has come into common use thanks to Kuhn--and now means different things to different people. In understanding Kuhn's use of "paradigm" it is helpful to start with his view that scientific work is primarily about "puzzle solving." Contrast this with "discovery." Think of the image of Sir Issac Newton sitting under a tree. An apple falls and Newton suddenly has an "Aha!" moment in which the law of universal gravitation pops into his head. That's discovery.

What actually happened is that Newton went to work on the problem of explaining what was already known from Kepler's observations about the motion of the planets. The law of gravitation was the resulting solution. That's puzzle solving.

"Discovery" implies surprise: you find something that you didn't know was there. Puzzle solving, on the other hand, implies that you know in advance what the solution will look like--the puzzle is in how to get from what you know to the desired solution. Puzzles also typically come with constraints. In a crossword puzzle, all the words need to share letters. In su doku every each number can only occur once in a row, column or square. In Rubik's cube you can't take the cube apart.

A paradigm gives scientists a picture of the solution--of what they need to figure out--and the constraints that must be satisfied in reaching that solution. Scientists working within a paradigm generally know where they are headed and know the accepted practices they will use to get there.

Thinking of science as puzzle solving is very different than thinking of it as discovery. It is an important difference when we think about science education.

Paradigms and Learning Progressions

Kuhn tells us that paradigms are essential to scientific progress. They provide a "map" for scientists to follow; normal scientific research is the exploration and elucidation of the detailed landscape charted by that map. Moreover, "paradigms provide scientists not only with a map but also with some of the directions essential for map-making." (p. 109)

When scientists try to work without a map (which is how science MUST work before a paradigm is established and broadly accepted) their writings are like those of the blind men describing an elephant. They talk past each other, working from different assumptions about what is real and what is important. We see some of this when we watch students present their research. There is a lot of "It could be this, or it could be that" without a way to connect to each other's work).

The other thing that we see when students engage in research without a good map of the landscape is confusion and frustration. (See the parable "Joe and the Hundreds of Holes.")

Thinking about all of this in terms of science education, it seems that TSSR is giving us important insights into the learning progression required to support student inquiry: We must somehow introduce students to the paradigm that encompasses the research they will undertake. How do we do that? If it were really a physical map, we could just draw it. But a paradigm is a map in a broader, metaphorical sense. How do we help students see the problem space covered by the paradigm? What are they key elements? How do they connect?

Kuhn suggests that the answer lies in the direction of having students solve a common core of problems. He notes that "Scientists solve puzzles by modeling them on previous puzzle-solutions." These "puzzle-solutions" become what he calls "exemplary problems." The value of having students work problems, either with pencil and paper or in the context of structured (contrived?) research settings is not just that they get better at solving problems: Working the problems introduces students to the accepted paradigm. They learn what to pay attention to, what to ignore, and how to see the world:

After he has completed a certain number [of exemplary problems], which may vary widely from one individual to the next, he views the situations that confront him as a scientist in the same gestalt as other members of his specialists' group. For him they are no longer the same situations he had encountered when his training began. He has meanwhile assimilated a time-tested and group-licensed way of seeing. (p. 189)

Citizen Science

My organization works with teachers to engage students in citizen science rooted in research in the National Parks. In the Northeastern United States, mercury pollution is impacting ecosystems. The students in the schools that we work with collect samples that we analyze for mercury content. Gathering information about mercury levels in target species in different ecological settings across the Northeast helps us construct a better picture of how mercury moves and where it settles. The idea is that as the students help scientists out by collecting samples, they learn earth science, biology, and chemistry. They also learn about their National Parks and--just as important--learn what scientists do and how they do it.

This kind of work--outdoors, working with issues that matter outside the classroom, engaged in research where no one (including the teacher) knows what the result will be--is a new experience for students and teachers. We see evidence of increased student engagement, but also see evidence that students need more preparation and background knowledge to get the most from the experience. (Again, see the parable "Joe and the Hundreds of Holes.")

Kuhn's focus on paradigms and on exemplary problems as a way to assimilate them--as a "time-tested and group-licensed way of seeing"--raises two important kinds of questions about the intersection of citizen science and science education:
  1. Citizen Science as Exemplary Problem: If we think of citizen science as a means to science education, we will ask, "Is the citizen science work a good exemplary problem? What is it an example of? Where does it lead? How do students build on the experience with us to get better at working these problems?"

  2. Exemplary Problems to Support the Citizen Science: Thinking instead of the citizen science as the goal--something that we want to build scaffolding in earlier grades to support--we will ask, "What kinds of exemplary problems should students work on in preparation for the citizen science experience? When should they do this, and how long will it take for them to acquire the "group-licensed way of seeing" that they need to engage productively in the citizen science?"
These two kinds of questions could be asked with regard to any activity in science education. Restated, they are "What future learning does this activity support?" and "What support needs to be in place before I do this activity?" But the questions come into particularly sharp focus for citizen science because students are engaged in real, useful research--not just schoolwork--and are doing it in collaboration with working scientists. Our program's value as an example of scientific work is why teachers sign on.

I don't have answers to these questions. Some of them have to do with what science educators and schools want to achieve. Others have to do with what works, what's possible, and what's necessary. All are questions that we need to explore over the next couple of years.

Hearing from others--both in response to these questions and in the form of additional questions--would be a good way to start on this work.

No comments:

Post a Comment