建构主义认为,世界是客观存在的,但对于世界的理解和赋予意义是由个人决定的。我们学习新知识时都是以已有的经验为基础来构建现实的~([1])。每个人的经验不同,对事物的理解不同,致使在后来的学习中对事物的认识不同。在教学过程中,教师应在理解学生不同认知的基础上,创设情境,教会学生建构新知识的方法,让学生自己内化新知识,形成新的知识结构。气体制备实验,学生初次接触会觉得比较难于理解,特别是气体发生装置和收集装置的选择是一个难点。这就要 Constructivism holds that the world is an objective reality, but the understanding and endowment of the world are individually determined. When we learn new knowledge, we build the reality based on the existing experience. ([1]) Each person’s experience is different, different understanding of things, resulting in later learning different understanding of things. In the process of teaching, teachers should create situations and teach students how to construct new knowledge based on the understanding of students’ different cognitions, so that students can internalize new knowledge and form new knowledge structure. Gas preparation experiments, students will feel more difficult to understand the initial contact, especially the choice of gas generating device and collecting device is a difficult task. This is necessary