Nature of science (NOS) becomes one of the major emphases in curriculum and assessment. This study explores what and how NOS is included in the Hong Kong biology curriculum and seven-year high-stakes assessments. Although there are different conceptualizations on the definition of NOS, the family resemblance approach (FRA) is used to analyze the inclusion of NOS in the curriculum and the high-stakes assessments. In FRA, NOS comprises a cognitive-epistemic system and a socialinstitutional system. There is a total of 11 categories in these two systems and these categories are interconnected with one another. By adopting Epistemic Network Analysis (ENA), the frequency of connections among these NOS categories in the curriculum and the high-stakes assessments can be visualized and compared. This study reveals three major findings: (1) both the curriculum and the high-stakes assessments neglect the NOS categories in relation to the social-institutional system;(2) the NOS categories included in the curriculum are not aligned with those included in the high-stake examinations; (3) the high-stakes examinations require students to demonstrate their NOS understanding using a limited range of skills in a limited range of contexts. Implications on the design of curriculum and assessment items will be discussed.

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BackgroundConstructing knowledge through collaborative practical work is a complex process and involves the use of multiple modalities by group members. In practical work sessions, students often manipulate visual objects or textual materials but do not develop their scientific ideas. PurposeThis study illustrates (a) the challenges that science students face when they create thematic patterns in a laboratory class and (b) characterizes the processes of how students make meaning of practical work activities. SampleDrawing from a video database, we chose to investigate an 80-minute chemistry lesson with eight Year 10 students who were unpacking the complex ideas behind practical work. This lesson episode was transcribed multimodally, with snapshots of the pictures of students' actions and gestures. MethodsThis study adopts a case-study approach. A multimodal discourse analysis approach was taken to examine the classroom discourse of the students when they were determining the strength of acids and alkalis through electroconductivity. ResultsWe identified various challenges when students integrated gestures, pictures and verbal discourse during practical work section. These challenges include those when students realize textual and visual modes and those when students associate components of apparatus into a system of functional set-up. Moreover, students cannot construct thematic patterns because they reorient their focus from the domain of ideas to the domain of objects and observables. The study recorded a number of strategies that students use to overcome these challenges that impede their meaning-making. ConclusionThe findings of this study contribute to the literature by identifying the challenges and strategies faced by students when they were connecting the scientific ideas with the practical work. When science education researchers advocate inquiry-oriented approach, they should provide ample scaffolds for these multimodal challenges.

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BackgroundPhotomicrographs are major biological representations which help students understand more about the structures of cells and tissues. Owing to their abstract nature, students often rely on representations in textbooks to develop their understanding of photomicrographs. PurposeThis study investigated how students with low, medium and high competence for visualizing photomicrographs integrated textbook representations into their understanding of photomicrographs. SampleTwelve, 14-15 year-old students who were studying biology in a UK secondary school participated in this study. Design and methodsWe carried out semi-structured interviews with these students. The modified model of integration of text and picture from Schnotz and Bannert ( 2003) was used to interpret students' verbal response and their drawing. An innovative discourse analysis approach, Epistemic Network Analysis, was used to analyse the connections between codes which were informed by the model. ResultsCompared to students with high competence, students with low and medium levels of competence did not necessarily understand the structure-behaviour-function relationship of the textual representation, or notice the visual elements in the diagrams. Hence, they could not transfer their understanding of textbook representations into that of the photomicrograph. ConclusionThis study suggests that the modified model of integration of text and picture can potentially reveal how students with different levels of visualization competence access information from textual and pictorial information. Equally importantly, the study argues for using epistemic network analysis as a tool to examine how students integrate textbook representations.