Using Rasch Modeling To Develop Computer Modeling-based Instruments For Measuring Middle School Students' Conceptual Understanding Of Structure Of Matte

Currently, science literacy is a common goal of science education around the world. To achieve the science literacy, students should develop their essentially understanding of science conceptions, what is the core component of science literacy for k-12 students. One concensus emerged in science education in last four decades had been shown that a wide range of misconceptions, alternative conceptions about science are held by students from kindegarden to senior high school and even to university sutudents, many of which are robust and static. Those misconceptions/alternative conceptions constrain students from fully and successfully understanding science conceptions. In chemistry education, one commonly agreeed primary source of students' misconceptions is their inabilities in making connections among different levels of representations (macroscopic, submicroscopic and symbolic representation). The inability to connect different levels and translate chemical representations has been shown to limit students'development of a strong conceptual understanding of chemical phenomena and concepts. Research further suggests that transforming different representations seamlessly requires adequate understanding of models and modeling in chemistry. To facilitate students to overcome those difficulties, numerous research has focused on how to enhance students'visualization abilities in chemistry and help students make connection among different chemistry representations. Recently, chemical educators have begun to use computer models to help students make connections among three levels of representations. Research has found that, computer modeling can make the submicroscopic representations dynamic, visual, and interactive, which enable students understand submicroscopic world behaviors, make connections among different levels of reprensentation, construct more science conceptions, and improve their reasoning, scientific inquiry skill and problem-solving ability.Inevitably, there is an obvious trend in science education of using computer modeling as learning tools to improve students' understanding of science concptions and science models. While chemistry teaching and learning based on computer models and modeling has shown promise to improve student understanding of chemistry concepts, measurement and assessment of students' conceptual understanding basing on computer modeling is pretty important and necessary. However, such area has lagged behind, because there are no computer modeling based instruments currently available to assess students'conceptual understanding of chemistry concepts. The present study creatively used Rasch modeling to develop computer modeling-based instruments for measuring middle school students' conceptual understanding of structure of matter, with Wiloson' (2005) "Four Buidling Blooks" as methodology framework. Conducting both theoretic and emperical studies, we further explored how to develop measurements and assessments on students' understanding of structure of matter basing on computer models.In theoreticl study, some key conceptions and theories, which are closely related to the present study, were discussed and summarized, e.g., multiple representations in chemistry education, science modeling, computer modeling, learning progressions, understanding of matter, understanding of structure of matter, Rasch modeling, and "four building blocks" of measurement constructing. Those theories are rationale for the study. Basing on numerous literatures analysis and synthesis, the present study proposed the learning progressions of structure of matter, which was used as theoreticl framework to guide the development, revision of measurement instruments and analysis and interpretation of data.In empirical study, there were three parts:(1) development of measurement instruements of high school students' understanding of structure of matter basing on computer modeling, (2) equating of these measurement instruments, and (3) primary investigation on how students understand structure of matter basing on computer modeling. Around 1,600 students of grade 9 and 10 in China and grade 10&11 in the United States took these tests in two rounds of Pilot-tests. The measurement instruments used in Pilot-test I were modified basing on the analysis of data through Rasch modeling, and then used in Pilot-testâ…¡. Similarly, the data generated from Pilot-testâ…¡was modeled and analysized by Rasch modeling to investigate the quality of measurement instruments. Anchor-test design was used to explore the equating of three measurement instruements, and a table of conversion between raw scores and 0-100 Rasch scale scores was produced, which is more convenient for the users and makes them avoid conducting Rasch analysis every time the instruments are used. The simultaneous estimations of items in three test forms also can be used to calculate the difficulties of each understanding level in a test form. Consequently, the validated measurement instruements was used to assess high school students' understanding of structure of matter basing on computer modeling. In term of quantitative and qualitative study of students' response, the study proposed a dynamically ecological learning model of structure of matter.The courrent study has shown that, the measurement instruments we developed and validated in this study have good reliability and validaty; anchor-test design of equating of measurement instruments which measure the same contruct is reasonable and effective, and it is useful to compare different tests with same contruct and draw students' progress of understanding over time; the learning progressions and dynamically ecological learning model of structure of matter appropriately describe students'learning characteristics and developmental model; the resuls of students' examination of three tests shown that grade 10 students' understandings of structure of matter basing on computer modeling are significantly higher than grade 9 students in China; grade 9 students appropriately stand in level 2 and grade 10 appropriately stand in level 3 of learning progression of structure of matter; students'understanding structure of matter involves understanding structure models of matter and using structure of matter to describe, interpret or predict properties and change of matter, which essentially integrate four components of understanding, i.e. compositions and structure, physical properties and change, chemical properties and change and conservation; the four components are connected and interactive and form a dynamically ecological learning model with the structure of matter at the center.In this study, we had explored an innovative method to use Rasch modeling to develop computer modeling-based measurement instruments on students' understanding of structure of matter. It provides an example for developing computer modeling-based measurement instruments focusing on some science concepts. We developed the learning progressions of structure of matter, and three measurement instruments. The measurement instruments were validated and equated. We manifested the understanding of high school students about structure of matter basing on computer model. Thus, the current study has both profoundly theoretic and practical meanings. At the end of this dissertation, the implications, limitations and further steps were also discussed.