Teaching Design of High School Geography Experiments Based on the PBL Teaching Model —Taking “Alluvial Fan” as an Example

高中地理包含众多尺度宏大、时间跨度长的抽象过程性知识，学生理解难度较大。地理实验作为具象化地理过程的重要载体，与Problem-Based Learning (PBL)教学模式深度融合，可为学生构建实践与探究兼备的学习体验。以“冲积扇”为例，基于PBL教学模式设计“真实情境创设–问题驱动求知–分析方法迁移”教学路径：以新疆玛纳斯河冲积扇的“荒漠变棉田”现实矛盾为起点，通过真实情境创设(卫星影像分析、绿洲扩张数据)，激发学生探究冲积扇形成机制的内在动机；依托问题驱动求知，设计梯度实验任务模拟“流水动力–沉积分异–扇体扩展”过程，将抽象机理转化为可观测、可量化的实践链条；最终通过分析方法迁移引导学生从微观实验结论推演宏观区域发展逻辑，培养学生解决实际问题的科学思维，为高中地理教学改革提供具有实践价值的思路。High school geography encompasses a multitude of abstract, process-oriented knowledge with large scales and long time spans, which poses significant challenges for students to understand. As a crucial vehicle for visualizing geographical processes, geographical experiments, when deeply integrated with the Problem-Based Learning (PBL) teaching model, can provide students with a learning experience that combines practice and exploration. Taking the “alluvial fan” as an example, a teaching path of “creating real-life scenarios-driving learning through problems-transferring analytical methods” is designed based on the PBL model: Starting from the real-world contradiction of “transforming deserts into cotton fields” in the alluvial fan of the Manas River in Xinjiang, by creating real-life scenarios (such as analyzing satellite images and data on oasis expansion), the students’ intrinsic motivation to explore the formation mechanism of alluvial fans is stimulated. Relying on problem-driven learning, gradient experimental tasks are designed to simulate the processes of “fluvial dynamics-sedimentary differentiation-fan expansion”, transforming the abstract mechanism into an observable and quantifiable practical chain. Finally, through the transfer of analytical methods, students are guided to deduce the macro-regional development logic from the micro-experimental conclusions, cultivating their scientific thinking in solving practical problems and providing practical ideas for the reform of high school geography teaching.