Argumentation is one of the discursive practices in scientific communities used to frame claims, weigh evidence, construct warrants, and discuss alternative explanations (Kuhn, 1993). In recent years, argumentation has been receiving increasing attention in science education studies (e.g., Driver, Newton, & Osborne, 2000; Osborne, Erduran, & Simon, 2004). The studies imply that argumentation plays a vital role in science learning and it should be reinforced in science classrooms (Duschl & Osborne, 2002; Kelly, Druker & Chen, 1998), because students who are engaged in argumentation not only advance in the social construction of scientific knowledge but also learn the nature of scientific enterprise (Bell & Linn, 2002). Although argumentation is seen as an effective instructional approach and educational goal for science education (e.g., Duschl, & Grandy 2005; Osborne et al., 2004), it rarely takes place in science classrooms (Osborne et al., 2004). Bricker and Bell (2008) argue that this is partially because of the failure of teachers or curriculum in reflecting the aspects of argumentation found in professional scientific practice. Thus, if science teachers are trained in argumentation practices similar to professional scientists’, argumentation will more widely be integrated into science classrooms. Herein lays the role of laboratory in providing opportunity not only to collect and analyze data in collaboration with others like a scientist, but also to engage in argumentation (Duschl, & Grandy, 2005). Laboratory provides a context in which science learners can engage in critical coordination of evidence and theory, scientific thinking and reasoning to support or reject an explanatory conclusion, model or prediction (Suppe, 1998; Osborne et al., 2004). However, there is little known about the argumentation practiced in the laboratory context, especially for the pre-service science teachers who are expected to bring the argumentation practices into their future science classrooms. Therefore, this study is aimed at investigating the argumentation practices of pre-service science teachers (PSTs) while they are engaged in laboratory work. It looks for the nature of pre-service science teachers’ argumentation during laboratory work. The research question directed this study is; What is the nature of arguments constructed by PSTs during laboratory activities?

Participants are 33 PSTs enrolled in their third year of four-year Elementary Science Education program in a large public university of Turkey. In the context of this study, participants worked in groups of four or five on two science topics, namely Hooke’s Law (developed by first researcher) and Evolution Theories (adapted from National Academy of Sciences, 1998). In general, groups working independently formulated a hypothesis, defined variables, designed an experiment, collected and recorded data, and communicated findings with other groups. Data were collected through focus group video-recording during the groups’ investigation and discussion period. The video records of two experimental parts and two critical discussion parts were transcribed. Pre-determined argumentation schemes developed by Walton (1996) were used for data analysis. The researchers independently categorized transcripts of the argumentative dialogues for argumentation schemes. Thus, the inter-rater consistency was tried to be achieved about categorization of argumentation schemes by the investigator triangulation.

In this study, it was found that participants used 15 argumentation schemes in science laboratory during investigation and discussion periods. These were argument from verbal classification, cause to effect, position to know, expert opinion, correlation to cause, sign, evidence to hypothesis, consequences, analogy, circumstantial argument against a person, vagueness of verbal classification, gradualism, commitment, bias and example. The most frequently used argumentation schemes were argument from sign and from evidence to hypothesis. It is important to note that arguments from evidence to hypothesis were only constructed during critical discussions. We interpreted this as usual since PSTs required using their data to be an evidence of their hypothesis in support. It can be concluded that wide range of argumentation schemes employed by participants suggests that laboratory supported with critical discussions is a learning context which allows dialogical reasoning.