Investigation into the Semantic Density and Semantic Gravity Wave Profile of Teachers When Discussing Electrophilic Aromatic Substitution (SEAr).

Philippa B Cranwell,Karin L Whiteside

doi:10.1021/acs.jchemed.0c00571

Abstract

Language in chemistry is highly specialized, and for students, transitions in language complexity from high school to university can be extremely challenging. With an increasingly diverse cohort of students enrolled in UK chemistry degree programs, better understanding the linguistic challenges students face is becoming a greater pedagogical priority. Spoken language plays a central role when learning chemistry, and any misunderstandings can lead to misconceptions that can impede students’ success in this demanding subject. This small-scale study sought to compare the complexity of spoken-language explanations of the same chemical process within UK secondary (high school) and university contexts. The study involved seven organic chemistry educators/teachers, four based in a UK university and three in a UK high school, discussing electrophilic aromatic substitution (SEAr) via a lecture or screencast. The participants’ spoken discourse was transcribed and coded according to the concepts of semantic gravity (the degree to which meaning relates to context) and semantic density (the degree to which meaning is condensed within symbols) drawn from Legitimation Code Theory, and then it was analyzed for semantic waves. When considering semantic gravity, there were some similarities and some differences. In all cases, semantic gravity was weaker, but participants based in a university environment generally tended to exhibit relatively weaker semantic gravity than their school-based counterparts. The school-based participants usually added further explanations to clarify what was meant during an explanation and exhibited semantic waves by unpacking and repacking a concept, whereas the university-based participants tended to show a flatter semantic profile. Findings showed that, across the levels of study investigated, semantic density was stronger: a similar complexity of chemistry-specific vocabulary used by all seven participants, regardless of the audience. Findings have pedagogical implications and suggest that a larger-scale study of semantic waves in oral chemistry discourse could usefully inform specific-purposes language teaching.

Highlights

Subject-Specific Language within Organic ChemistrySuccessful study in chemistry requires “vertical integration” of knowledge, with the learning and understanding of basic concepts and ideas acting as foundations for further study.[1−3] Organic chemistry is challenging because when learning about reactions and transformations there are two aspects that students need to master in order to succeed
It should be noted that this study focuses only on the language used by the participants and does not attempt to probe the relationship between spoken discourse and reference to diagrams
When discussing attack by the benzene onto the chlorine molecule, participant E states: “Electrons will come out of the benzene-ring and they will form a bond between the carbon and the chlorine, so our intermediate has still got the hexane of the benzene-ring and because this is the carbon, that let’s say, that the electrophile up here has attacked the π-cloud at the top means the chlorine will be above the plane of the ring so we show that with a wedge and that forces the hydrogen down below the ring, so we show that as the dashes

Summary

Introduction

Subject-Specific Language within Organic ChemistrySuccessful study in chemistry requires “vertical integration” of knowledge, with the learning and understanding of basic concepts and ideas acting as foundations for further study.[1−3] Organic chemistry is challenging because when learning about reactions and transformations there are two aspects that students need to master in order to succeed. Students need to become proficient with the subject-specific language used, and second, students need to become fluent at using and understanding visual representations of reactions and chemical transformations.[4−7] Kozma and Russell[8] show that the ability of students and instructors to represent chemical happenings in different ways is important, and they suggest that language has a key role in holding different representations together. Technical language has to be used carefully so that meanings are not lost or altered.[9] Bernstein characterizes the language of chemistry as “vertical discourse” and states that “...vertical discourse takes the form of coherent, explicit, and systematically principled structure, hierarchically organized as in the sciences, or it takes the form of a series of Received: June 5, 2020 Revised: July 21, 2020 Published: August 13, 2020.

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