做好科学教育加法、推进科学教育高质量发展已成为新时代开展科学教育的目标，而课堂作为教学的主阵地，提高科学课堂教学质量是做好科学教育加法的落脚点和突破口。目前，显性直接教学在国外的许多学校和课堂中已经得到了广泛应用并取得了显著成效，特别是在教授知识技能和培养高阶思维方面。显性直接教学旨在以“精心地教学设计”“高效地教学方式”让包括学困生在内的每一位学生达成学习目标，获得更好的学习体验。大量研究表明，在这样的课堂上，学生学得更快更多，这为“双减”背景下做好科学教育加法提供了新的理论视角。尤其是，优质的科学课堂教学中很可能蕴藏着显性直接教学的活动和策略，探索其隐含的特征与规律可以更好地为科学课堂建设提供借鉴。因此，本研究以显性直接教学为理论视角，构建小学科学课堂的分析框架，并以其作为主要研究工具对小学科学课堂教学进行分析研究，总结提炼高效且优质的课堂教学行为模式，为一线教师教学改进提供参考范例，进而提升科学课堂教学质量。
首先，研究通过文献调研，归纳梳理显性直接教学的设计框架和教学策略，并对其教学策略下的核心教学行为进行拆解，初步构建得出显性直接教学视角下的科学课堂分析框架。之后，通过两轮德尔菲咨询和试测分析，构建了显性直接教学视角下的科学课堂分析框架。其次，基于显性直接教学视角下的科学课堂分析框架，对20节新手教师和21节专家教师的执教课例展开研究，分析了我国目前小学科学课堂中显性直接教学策略（认知建模、检查理解、支架渐隐和分层干预）的应用频率、行为特征以及新手教师与专家教师的差异。最后，使用滞后序列分析法对小学科学课堂上显性直接教学行为进行分析得出显性直接教学策略的有意义行为序列，提取适用于我国小学科学课堂的显性直接教学行为模式，并对新手教师和专家教师的使用方式进行了对比分析。
研究发现：（1）显性直接教学已经在无形中广泛应用于我国小学科学课堂教学中，教师的行为在一定程度上与显性直接教学的思想一致，但在支架渐隐策略的使用方面有待提升，实际课堂教学中缺乏系统的支架渐隐策略的使用。（2）“TM→TTA”（“教师建模→教师出声思考”）是认知建模的核心教学行为序列，“AQ→LI→EF”（“提问→倾听→有效反馈”）是检查理解的核心教学行为序列，“GP→IP”（“有指导的练习→独立练习”）是支架渐隐的核心教学行为序列。而分层干预教学策略不会在教学中单独出现，往往融入到认知建模、检查理解中使用，以调节不同学生学习进度，保持学生学习步调的一致性。（3）新手教师和专家教师在使用认知建模、检查理解和分层干预策略的频次和时间上并无显著统计学差异，各教学行为的出现频次及频率也并无不同。但在支架渐隐教学策略的使用上，专家教师在课堂上使用时长明显高于新手教师。（4）新手教师和专家教师在使用检查理解、支架渐隐和分层干预教学策略时表现出明显一致的使用模式，但在认知建模的使用路径上存在明显不同。
本研究的研究意义在于：（1）本研究构建了显性直接教学视角下的科学课堂分析框架，有助于为小学科学课堂的教学分析和效果评估提供可操作的工具。（2）本研究分析了显性直接教学在小学科学课堂中应用的可行性，进一步拓展了显性直接教学的应用范围，提供了小学科学课堂观察分析的新角度。（3）本研究基于所构建的课堂分析框架对当前新手教师和专家教师所执教的科学课堂教学进行了分析并提炼了其教学模式，有助于帮助小学科学教师形成对显性直接教学的系统性认识，为教师在课堂中采用显性直接教学策略提供了可参考的教学模式。

Enhancing science education and promoting its high-quality development have become the goals for conducting science education in the new era. The classroom, being the main battlefield for teaching, is the pivotal point and breakthrough for improving the quality of science classroom teaching, which is essential for the addition to science education. Currently, explicit direct instruction has been widely adopted and has demonstrated significant effectiveness in classroom teaching, particularly in the instruction of knowledge and the cultivation of higher-order thinking. Explicit direct instruction aims to enable every student, including those who struggle academically, to achieve learning objectives and gain a better learning experience through “the Well-Crafted and Well-Taught lesson”. Numerous studies have shown that explicit direct instruction helped students learn more effectively and quickly, providing a novel theoretical perspective for enhancing science education in the context of the “Double Reduction” policy. In particular, high-quality science classroom likely encompass activities and strategies of explicit direct instruction. Exploring and discovering their implicit characteristics and patterns can provide valuable insights for the construction of science classrooms. Therefore, this study adopted explicit direct instruction as a theoretical perspective, constructed an analytical framework for elementary school science classroom, and employed the analytical framework to analyze and study elementary school science classroom teaching. The study aimed to summarize and refine efficient and high-quality classroom teaching patterns to provide reference models for teachers to enhance the quality of science classroom teaching.

Firstly, the study conducted a literature review to summarize the design framework and pedagogical strategies of explicit direct instruction, analyzed the core teaching behaviors under its pedagogical strategies, and preliminarily constructed an analytical framework for elementary school science classrooms from the perspective of explicit direct instruction. Secondly, this study, through two rounds of Delphi consultation and pilot test, ultimately constructed the analytical framework for elementary school science classrooms from the perspective of explicit direct instruction. Then, based on the analytical framework, this study studied 20 lessons taught by novice teachers and 21 lessons by expert teachers, analyzed the frequency, behavioral characteristics, and differences between novice and expert teachers in the use of explicit direct instruction strategies (Modeling, Checking for Understanding, Scaffold Fading, and Intervention) in current elementary school science classrooms in China. Finally, this study employed lag-sequential analysis to analyze explicit direct instructional behaviors in primary school science classrooms and to reveal meaningful sequences of these strategies. Furthermore, this study extracted patterns of explicit direct instruction applicable to primary school science classrooms in China and conducted a comparative analysis of the usage methods between novice and expert teachers.

The findings of the research indicated that: (1) Explicit direct instruction has been widely used in primary school science classrooms in China. Teachers' behavior was consistent with the idea of explicit direct instruction to a certain extent. However, there was room for improvement in the application of scaffolding fading, and there was a lack of systematic use of the strategy in actual classroom teaching. (2) “TM→ TTA” ( “Teacher Modeling→ Teacher Thinking Aloud” ) was the core instructional behavior sequence of modeling, “AQ→ LI→ EF” ( “Asking a Question→ Listening → Effective Feedback” ) was the core instructional behavior sequence of checking for understanding, and “GP→ IP” ( “Guided Practice→ Independent Practice” ) was the core instructional behavior sequence of scaffold fading. Intervention did not appear alone in teaching, but was often integrated into modeling and checking for understanding to adjust the learning progress of different students and maintain the consistency of students' learning pace. (3) There was no statistically significant difference between novice teachers and expert teachers in the frequency and time of using modeling, checking for understanding, and intervention strategies, and there was no difference in the frequency of each teaching behavior. However, when it comes to the scaffold fading, the expert teachers spent more time in class than the novice teachers. (4) Novice teachers and expert teachers showed significantly consistent patterns when using the teaching strategies of checking for understanding, scaffold fading and intervention, but there were significant differences in the use paths of modeling.

The findings of this study have several contributions. First, this study developed an analytical framework for elementary school science classrooms from the perspective of explicit direct instruction, which provides an operational tool for teaching analysis and effectiveness evaluation in primary school science classrooms. Second, this study analyzed the feasibility of application of explicit direct instruction in primary school science classrooms, further expanding the application scope of explicit direct instruction, and providing a new perspective for observation and analysis in primary school science classrooms. Third, based on the analytical framework, this study analyzed and refined the teaching patterns of current science classes taught by novice and expert teachers, which can help primary school science teachers develop a systematic understanding of explicit direct instruction and provide a reference for teachers to adopt explicit direct instruction strategies in the classroom.