Sustainability has become a prominent theme in society and can be considered as an integral part of scientific citizenship. This study investigates to what extent the production, use and re-use of (bio)plastics initiates students’ reasoning and to identify the kind of content knowledge students put forward. The structure of students’ arguments was mapped according to Toulmin's model of argumentation, i.e., claim, data, warrant & backing and qualifier & rebuttals. Students (N = 27, grade 10 & 11) participated in groups of three. The students were introduced to the topic of the production, use and re-use of plastics by watching a video, answering questions, reading articles and having interviews and group discussions. Students were prompted to argue on the sustainability of bioplastics and fossil-based plastics. The results show that students frequently used arguments related to preventing pollution, designing to recycle and designing to degrade. However, themes such as avoiding waste, origin of energy and materials, energy efficiency and costs were rarely used or even absent in students’ reasoning. Overall, the students’ reasoning contained all of Toulmin's categories, and especially the increase in the number of qualifier & rebuttals is interpreted as an indication of awareness of the complexity of the issue at hand. This study underlines that students are able to bring in relevant scientific knowledge when confronted with a suitable sustainability issue, but also more societally oriented arguments enriched their perspective. Implications for the design of interventions aiming to engage students in life cycle analysis (on plastics) are discussed.

中文翻译：

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大学前学生对生物塑料和化石塑料生命周期的看法

可持续发展已成为社会中的一个突出主题，可以被视为科学公民的组成部分。本研究调查了（生物）塑料的生产，使用和再利用在多大程度上引发了学生的推理，并确定了学生提出的知识内容的种类。根据Toulmin的论证模型，即索赔，数据，权证和支持以及限定词和反驳，绘制了学生论证的结构。学生（N= 27、10和11年级）参加了三个小组。通过观看视频，回答问题，阅读文章以及进行访谈和小组讨论，向学生介绍了塑料的生产，使用和再利用的主题。提示学生就生物塑料和化石塑料的可持续性争论。结果表明，学生经常使用与防止污染，设计回收和设计降解有关的论点。但是，在学生的推理中很少使用甚至避免诸如避免浪费，能源和材料的来源，能源效率和成本等主题。总体而言，学生的推理包含了Toulmin的所有类别，尤其是限定词和 反驳被理解为对当前问题复杂性的认识的一种指示。这项研究强调，面对适当的可持续性问题，学生能够吸收相关的科学知识，而且更注重社会取向的论点丰富了他们的视野。讨论了旨在使学生参与生命周期分析（关于塑料）的干预措施的设计含义。