Chlorine: Undergraduate Research on an Element of Controversy

Chemical Education Today

Commentary

Chlorine: Undergraduate Research on an Element of Controversy by Hasok Chang

If chemical elements were people, chlorine would be a celebrity. Although intrinsically no more or less important than any other element, chlorine has had a knack of making headlines. It was surrounded in controversy right from its “birth”, or rather its first isolation, by Carl Wilhelm Scheele in 1774. Scheele actually did not think of it as an element, and called it “dephlogisticated marine acid”, marine acid (or muriatic acid) being the old name for hydrochloric acid. When Antoine-Laurent Lavoisier and his colleagues overturned the phlogiston theory, they re-named our curious substance “oxygenated muriatic acid”. The definite confirmation of its elemental nature only came with Humphry Davy’s work in the 1810s, also bringing down Lavoisier’s theory of acids, which presumed that all acids, including marine acid, contained oxygen. Afterwards chlorine also featured prominently in other debates about fundamental issues in the theory of matter, including Prout’s hypothesis and the solar neutrino problem. On the side of practical applications, chlorine gas still has emblematic status as the first major chemical weapon, unleashed one fine spring day in 1915 in the fields near Ypres, Belgium, in a daring German operation directed by the renowned chemist Fritz Haber. At the same time, chlorine and chlorine compounds have also worked as life-saving disinfectants, and as major resources for chemical industry. The familiar smell of chlorine in swimming pools and household bleaches is a reminder of the widespread practical use of chlorine compounds. Chlorine was even touted as a cure and preventative for respiratory diseases in the wake of the flu pandemic of 1918–19 that killed at least 20 million people worldwide and left the medical establishment helpless. Even U. S. president Calvin Coolidge endorsed the treatments he received in a “chlorine chamber” installed by the U.S. government in Washington. The political controversy surrounding chlorine continued for the rest of the 20th century, particularly in relation to the use of organic chlorine compounds, ranging from the herbicides used by the U.S. forces in Vietnam (including the infamous Agent Orange) to DDT and other insecticides whose environmental impact was hotly debated following the publication of Rachel Carson’s Silent Spring (1) in 1962. Following the life of such a controversial substance makes a wonderful way of engaging students in chemistry from a historical angle, both intellectual and social, as we have learned in our collective undergraduate research project at University College London. The results produced by our students were collected and published in 2007 in An Element of Controversy: The Life of Chlorine in Science, Technology, Medicine and War (2, 3), the latest number in the monograph series of the British Society for the History of Science. I directed the project throughout, with the essential collaboration of Catherine Jackson in the last year of teaching and in the editing of the volume.

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The genre of “object biography” has been quite successful in popular science recently. Prominent examples include The Shocking History of Phosphorus (4) by John Emsley; H2O: A Biography of Water (5) by Philip Ball; and Cod: A Biography of the Fish That Changed the World (6) by Mark Kurlansky. But in scholarly history of science object biographies have not been so popular, despite some pioneering instances such as Neptune’s Gift: A History of Common Salt (7) by Robert Multhauf; Biographies of Scientific Objects (8) edited by Lorraine Daston; and Representing Electrons: A Biographical Approach to Theoretical Entities (9) by Theodore Arabatzis. We took this gap in the professional literature as a promising opportunity, as a “biographical” study of chlorine with its wide range of interesting controversies seemed very well suited for attracting and maintaining the enthusiasm of the diverse range of students we teach in our department. Inherited Research Work The vehicle for our project, carried out from 2000 to 2005, was a one-term undergraduate course open both to students taking history and philosophy of science as their major subject, and to science students who had done at least one relevant introductory course in history or philosophy of science. Pedagogically the most distinctive feature of our project was the mechanism of “inheritance”: accepting that in most cases even the best undergraduate students would not be able to produce publishable material in a one-term course, we asked students at the end of each year to pass on the fruits of their research (including all of their research notes) to the students taking the course in the following year. This process was repeated on each topic until publishable materials were produced. The inheritance mechanism was an essential piece in our attempt to turn this undergraduate class into an evolving community of real researchers. Each student had her or his own individual project, but built on inherited work, and also maintained close contact with other students working on related topics. Students learned to function just as scholars in a professional research community do, treating each other as expert colleagues, and each other’s work as secondary literature. Rather than treating undergraduate research as a preserve of the best and the brightest, or a vehicle for getting students to assist with projects already conceived by their teachers, our mode of work was designed to make independent research a routine part of undergraduate education for ordinary students. It was essential to do this work in a class rather than in dissertations or special research projects. Meeting in regular lectures and seminars gave students ample opportunity to get to know each other, and allowed me to give strong and detailed advice and instruction to students not yet adept with research methods. We even had an exam in the course, which forced students to learn about

Journal of Chemical Education • Vol. 86 No. 4 April 2009 • www.JCE.DivCHED.org • © Division of Chemical Education


each other’s work and gave them a chance to reflect on research methodology in a structured way. All stages of our work necessitated unusual and innovative methods, and a different mind-set from what usually prevails in an undergraduate classroom. To start with, we had the challenge of convincing students that they were really going to produce some real knowledge, not merely deliver the “right” answers that I already knew. To that end, it was important that I was not an expert on the particular topics being investigated, though I was knowledgeable and skilled enough in the general subject area to be able to guide the students’ work and to command their respect and trust. This principle of “removed expertise” was most strikingly applied in the project on “chlorine chambers” (2, chapter 9). That work began with a few mysterious lines I had stumbled upon in a popular chemistry book, Man and the Chemical Elements (10) by J. Newton Friend: “Very small amounts of chlorine in the air help to ward off colds and to relieve them when once they have gained a hold.” (p 48) But Friend gave no sources, and even various historians of medicine that I consulted had not heard of this episode. So I challenged the students to go and find out about it. David Nader and Spasoje Marčinko took up this challenge. After a good deal of initial struggle, they unearthed a wonderful story of how chlorine chambers were promoted by the U.S. Chemical Warfare Service (CWS) in a bid to prolong its existence after the First World War, and how they were quickly dropped once the CWS found a more convenient public-relations vehicle in insecticides. Originality The principle of removed expertise also helped us introduce another key pedagogical principle: the relativity of originality. Scholarship today is hampered and distorted by an unrealistic and illusory ideal of originality in which nothing counts as “original” unless it can be shown that no one at all in the history of the entire world has ever said it before. A more meaningful measure of originality is whether it is something previously unknown in the community one works in. In the context of our course, students were deemed to be producing original results if they discovered things that I did not know about. It often happened that the first person investigating a topic was mostly retracing the steps of some previous scholars, though I was not aware of that previous work. As students learned more and more, they made contact with more expert scholars elsewhere, and climbed up the ladder of originality until they were able to reach levels good enough to withstand professional peer review by leading experts. But in order to get on the ladder at all without being intimidated away from the whole process, students needed to be given the licence to enjoy their work at each level as genuinely original research. Flexibility The inheritance mechanism worked out as we had hoped, to a large extent. For instance, the work on the history of chemical disinfection (2, chapter 6) proceeded in three steps.

…this project on the history of chlorine serves as an effective testimony that learning, at a relatively early stage, can take the form of knowledge-production, going beyond knowledge-acquisition.

First, Elinor Mathieson started off with a good survey of early short-lived attempts at chlorine disinfection dating back to the late 18th century. Fiona Scott-Kerr inherited this work and gave a clearer shape to the story with her thesis that disinfection processes became established only when they were backed up by the germ theory of disease. In the following year Anna Lewcock fleshed out that story by focusing on the cholera epidemic of the early 1830s and finding subtler themes such as the conflict between chemists and physicians. Not all cases worked out in such a linear fashion. Sometimes a single student managed to finish up a topic to a very high standard, as in the case of Ruth Ashbee on the initial chemical disputes on the nature of chlorine in the midst of the Chemical Revolution (2, chapter 1), and Kimm Groshong on the controversy surrounding the publication of Silent Spring (2, chapter 11). Often more than one student wanted to work on a given topic in the same year, requiring a division of labor rather than a sequential accumulation. The mode of work had to be worked out in a creative way at each particular juncture. For example, in the first year of the project three different students came forward to investigate the fascinating story of solar-neutrino detection with a huge vat of dry-cleaning fluid (C2Cl4) buried 1,500 meters underground in a disused gold mine. So we divided up the project into three different aspects: scientific, sociological, and philosophical (taken up by Chris Guy, Lisa Murch, and Andrew Clegg, respectively). How exactly did this method develop, of capturing the elusive neutrino by its very occasional interaction with chlorine-37 turning it into radioactive argon-37; what was the sociological process by which consensus was first prevented and at last reached among scientists on this contentious issue; and given the elaborate chain of reactions and their interpretations, in what sense can we say this is really an instance of “observation”? And then Emma Goddard in the following year had the task of pulling those three strands together. In a subsequent year Emily Milner inherited that synthesis and expanded on the technical details of recent neutrino-detection projects and explored the philosophical questions about the nature of observation in more depth (2, chapter 4). It is impossible to mention here all the authors who made valuable contributions to the 11 chapters of the book, but each chapter embodies a particular history and dynamic of collaboration reflecting its own particular necessities and displaying its own unique merits.

© Division of Chemical Education • www.JCE.DivCHED.org • Vol. 86 No. 4 April 2009 • Journal of Chemical Education

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Commentary Doing By Learning Our experience with this project on the history of chlorine serves as an effective testimony that learning, at a relatively early stage, can take the form of knowledge-production, going beyond knowledge-acquisition. This is what I call the principle of “doing by learning,” to complement the familiar notion of “learning by doing.” (A full discussion of the pedagogical process and principles can be found in the book’s Epilogue (2).) Just as trainee doctors treat real patients, and trainee hairdressers cut real people’s hair, there is no reason why students, who are trainee scholars, should not routinely learn their trade through a process of making real contributions to knowledge. Literature Cited 1. Carson, Rachel. Silent Spring; Houghton Mifflin: Boston, 1962. 2. An Element of Controversy: The Life of Chlorine in Science, Technology, Medicine and War; Chang, Hasok; Jackson, Catherine, Eds.; BSHS Monographs 13; British Society for the History of Science: London, 2007. 3. Pence, Harry E. J. Chem. Educ. 2008, 85, 1055. 4. Emsley, John. The Shocking History of Phosphorus; Macmillan: London, 2000.

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5. Ball, Philip. H2O: A Biography of Water; Weidenfeld & Nicolson: London, 1999. 6. Kurlansky, Mark. Cod: A Biography of the Fish That Changed the World; Penguin: London, 1997. 7. Multhauf, Robert. Neptune’s Gift: A History of Common Salt; Johns Hopkins: Baltimore, 1978. 8. Biographies of Scientific Objects; Daston, Lorraine, Ed.; University of Chicago Press: Chicago, 2000. 9. Arabatzis, Theodore. Representing Electrons: A Biographical Approach to Theoretical Entities; University of Chicago Press: Chicago, 2006. 10. Friend, J. Newton. Man and the Chemical Elements; Griffin: London, 1961.

Supporting JCE Online Material http://www.jce.divched.org/Journal/Issues/2009/Apr/abs418.html Abstract and keywords Full text (PDF) with link to cited JCE article

Hasok Chang is in the Department of Science and Technology Studies, University College London, Gower Street, London WC1E 6BT, United Kingdom; [email protected].



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Chlorine: Undergraduate Research on an Element of Controversy

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