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Asia-Pacific Forum on Science Learning and Teaching, Volume 16, Issue 2, Article 7 (Dec., 2015) |
Research Design
This study used quantitative research design in a decision-making structure (Archila, 2015; Jho, Yoon & Kim, 2014; Maloney, 2007). This method was particularly useful to determine the percentage of participants considered each evidence provided by Scheele, Priestley and Lavoisier to be adequate in the controversy, “Who discovered oxygen?”. Another advantage of this method was the possibility of having more data about students’ assessment of evidence relating to experimentation in science and scientific communication.Qualification of the instructor
The chemistry teacher is a high teacher with 32 years’ experience and with a strong background in chemistry and physics. She participates in various working groups at the academic level. When the data of this research were taken, she knew the 63 students for 4 months. It is important to keep in mind that the chemistry teacher in this study assumed the role of a facilitator; her sole function was to encourage the students.Data collection
This study was conducted in a high school in Melun, France. The participants represented a wide range of achievement levels—low, medium and high, based on the chemistry grades of the previous semester. Data were collected from the written responses of 63 participants (24 females and 39 males aged 16–17 years) from households of middle-class socio-economic status. This data collection was conducted in two phases. In the first phase, the participants read Scene 8 of the French version of the play “Oxygen” (Djerassi & Hoffmann, 2003), which has an extension of 1650 words. The intervention of the chemists’ wives was deleted to better focus the learners’ attention on the experimentation in science and scientific communication recreated in this drama. Scene 8 can be briefly described as follows:The Chemistry Committee of the Royal Swedish Academy of Sciences decides to focus on the discovery of Oxygen, since that event launched the modern chemical revolution. But who should be so honored? Lavoisier is a natural choice, for if there ever was a marker for the beginning of modern chemistry, it was Lavoisier’s understanding of the true nature of combustion, rusting, and animal respiration, and the central role of oxygen in each of these processes, formulated in the period 1770-1780. But what about Scheele? What about Priestley? Didn’t they first discover oxygen?
Indeed, on an evening in October 1774, Antoine Lavoisier, the architect of the chemical revolution, learned that the Unitarian English minister, Joseph Priestley, had made a new gas. Within a week, a letter came to Lavoisier from the Swedish apothecary, Carl Wilhelm Scheele, instructing the French scientist how one might synthesize this key element in Lavoisier’s developing theory, the lifegiver oxygen. Scheele’s work was carried out years before, but remained unpublished until 1777.
Scheele and Priestley fit their discovery into an entirely wrong logical framework—the phlogiston theory—that Lavoisier is about to demolish. How does Lavoisier deal with the Priestley and Scheele discoveries? Does he give the discoverers their due credit? And what is discovery after all? Does it matter if you do not fully understand what you have found? Or if you do not let the world know?
In a fictional encounter, the [Scene 8] brings the three protagonists [Carl Wilhelm Scheele, Joseph Priestley and Antoine Laurent de Lavoisier] and their wives [Sara Margaretha Pohl, Mary Priestley and Anne-Marie Pierrette Paulze Lavoisier] to 1777 Stockholm at the invitation of King Gustav III [...]. The question to be resolved: “Who discovered oxygen?” […]. In the Judgment of Stockholm, a scene featuring chemical demonstrations, the three discoverers of oxygen recreate their critical experiments (Djerassi & Hoffmann 2001b, pp. 4–5).
Scene 8 was chosen because in it, each of the three chemists faces continuous pressure to defend his title as the true discoverer of this gas. In this scene the evaluation of evidence offered by each chemist is crucial.
In the second phase, the participants answered the following questions:
- Are Scheele’s arguments adequate? Explain why or why not.
- Are Priestley’s arguments adequate? Explain why or why not.
- Are Lavoisier’s arguments adequate? Explain why or why not.
The chemistry teacher supervising the session did not participate in any way while the students were answering the three aforementioned questions. She took care not to influence their decisions by demonstrating and maintaining her neutrality. Thus, the students did not know a priori if the evidence presented by the three chemists was correct or not. Requiring the participants to support their answers with reasons (“explain why or why not”) forced them to evaluate the evidence at hand.
Data analysis
The participants’ responses constitute the data of this study. These responses were assumed to result from their evaluation of the evidence. All the data were analyzed by the author. It should be pointed out that all the evidence recreated in Scene 8 is correct (Bensaude-Vincent & Van Tiggelen, 2003). The author classified this evidence as two types: (i) experimentation in science and (ii) scientific communication. The aim of this classification was to provide criteria for identifying and classifying the participants’ responses. The evidence corresponding to each of these types is presented below (Djerassi & Hoffmann, 2003):
Experimentation in science
Scheele’s evidence
- “Dissolve silver in acid of nitre and precipitate it with alkali of tartar. Wash the precipitate, dry it and reduce it by means of the burning lens in your apparatus […] A mixture of two airs will be emitted and pure silver left behind [talking to Lavoisier]” (p. 93).
- “I did that experiment in 1771, in a pharmacy in Uppsala with equipment much more modest than now put at our disposal by your Majesty [King Gustav III]” (p. 95).
- “I obtained the air over the next three years in many different ways, including red mercurius calcinatus, as you did [talking to Priestley]” (p. 95).
Priestley’s evidence
- “I made that air by heating mercurius calcinatus in 1774” (p. 92).
- “In August of 1774, I exposed mercurius calcinatus, the red crust that forms as mercury is heated in air, in my laboratory to the light of my burning lens. As the red solid is heated, an air will be emitted, while dark mercury globules will condense on the walls of the vessel. You will collect the air by bubbling it though water. As soon as the gas appears […] catch it under water” (p. 96).
Lavoisier’s evidence
- “I have brought from Paris a suit of rubber I have devised. It catches all the effluents of the body to show us that the equation balances” (p. 99).
- “I had begun my experiments with mercurius calcinatus …” (p. 102).
Scientific communication
Scheele’s evidence
- “In my book, about to appear” (p. 92).
- “The experiment I brought to your attention some three years ago in my letter [talking to Lavoisier]” (p. 93).
- “I told Professor Bergman [about the discovery]. I thought he would tell others” (p. 95).
Priestley’s evidence
- “I communicated that discovery in the same year [1774]” (p. 92).
Lavoisier’s evidence
- “[talking to Scheele] I know of no letter” (p. 93).
