To assess students’ conceptual understanding levels and diagnose alternative frameworks of the electrolyte concept, a measurement instrument was developed using the Rasch model. This paper reports the use of the measurement instrument to assess 559 students from grade 10 to grade 12 in two cities. The results provided both diagnostic and summative information about students’ conceptual understanding, suggesting that this measurement instrument had a certain validity. The results also demonstrated that Chinese mainland senior students’ understanding improved with increasing grade level, but that many alternative frameworks were entertained by students at each level.
This study uses graphs of conductivity measured by a microcomputer-based laboratory (MBL) to promote students’ macro, micro, and symbolic representations when learning about net ionic reactions (NIR). A total of 54 students, aged 14–15 years old participated in this research, and were randomly divided into an experimental group (N= 27) and a control group (N= 27). The students in the experimental group were given graphs of conductivity measured by MBL, while the control group had a demonstration of acid–base titration experiments. The results reveal that the graphs of conductivity have a large effect on students’ macro, micro, and symbolic representations, that is, the students in the experimental group build more representations than the students in the control group.
The galvanic cell is a basic concept in electrochemistry. To assess mainland Chinese students’ proficiency levels in galvanic cells, the Galvanic Cell Proficiency Level Assessment (GCPA) was developed based on the Rasch model. The GCPA was developed through a pilot test and consists of seven multiple-choice questions and four open questions. The assessment instrument was administered to 621 high school students in the 11th grade, and the test results showed good reliability and validity. The interview results supported the validity of the data generated by the instrument.
Background
In many countries and regions, such as the United States, Europe and China, a trend has emerged in which students’ enthusiasm for STEM is declining. This decline may be related to students’ lack of science self-efficacy. An accurate examination of students’ science self-efficacy can provide a research foundation for how to cultivate it. This paper used mixed methods to develop a valid science self-efficacy scale for high school students, focusing on the perceived competence dimension. A cross-sectional analysis exploring and interpreting differences across grades and genders in science self-efficacy among high school students was conducted. Subsequently, a 1-year longitudinal study was conducted on the development of science self-efficacy in China.
Results
This study developed a 24-item science self-efficacy instrument based on the Rasch model, and the validity of the instrument was assessed through multiple aspects, including face, content, construct, and predictive validity. This instrument was used to divide students' science self-efficacy into four different levels. A cross-sectional study examining 1564 high school students in 10th–12th grades revealed that students’ science self-efficacy exhibited a complex process of decreasing and then increasing by grade. Most girls’ science self-efficacy was higher than that of boys for Levels 1 and 4, while for the intermediate levels, i.e., Levels 2 and 3, most boys had higher science self-efficacy than girls. The quantitative and qualitative results of the longitudinal study through a 1-year follow-up of 233 high school students indicated that students’ science self-efficacy significantly improved. We revealed inconsistencies between cross-sectional and longitudinal studies of the change in science self-efficacy from 10 to 11th grade.
Conclusions
This study makes many contributions. First, we developed a science self-efficacy measurement instrument for high school students with high reliability and validity based on the Rasch model and characterized four different levels of student science self-efficacy. Second, the gender differences in science self-efficacy and the complex changes among grades were explained from the perspective of science self-efficacy level. Finally, students’ science self-efficacy significantly improved in the longitudinal study, which was explained by self-efficacy theory and the Chinese core competency-oriented science curriculum.
Students have various conceptions of electrolytes in learning chemistry. The aim of this study is to identify 10th grade students’ understanding of the electrolyte concept by using a phenomenographic method. Eight students, whose abilities were at different levels, were selected and interviewed. The findings show that four distinctive categories of students’ conceptions of electrolytes are demonstrated, and a hierarchy in terms of the logical progression among them can be developed. Finally, teaching implications are given.
Chemistry core ideas play an important role in students' chemistry learning. On the basis of the representations of chemistry core ideas about substances and processes in the Chinese Chemistry Curriculum Standards (CCCS) and the U.S. Next Generation Science Standards (NGSS), we conduct a critical comparison of chemistry core ideas between these two documents in this paper. We also discuss the following reasons why there are differences in the representation of chemistry core ideas between them: different research perspectives on science education, different understandings of chemistry core ideas, and different understandings of the nature of teaching process. Our primary intent in this comparative analysis is to promote a deeper understanding of chemistry core ideas, provide advice and resources for chemistry curriculum research and chemistry teaching practice, and raise more attention on goals of science education and aims of chemistry.
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