科学前概念既是儿童概念认知的过程，也是其概念认知的结果。它直接影响到儿童对科学概念的正确理解，影响到科学课堂的有效教学，影响到科学教育的质量。国际科学教育领域对儿童科学前概念的研究趋于成熟，已将科学前概念作为一种重要的课程与教学资源，但是我国对小学生科学前概念的研究一直比较薄弱。 本研究立足“水的液气相变”主题，选取了北京市2所小学402名学生，分别运用问卷、绘图和基于事件访谈等方法，从以下四个层面对6-12岁儿童的科学前概念进行探究：一是内容层面，藉改编的科学前概念探测工具挖掘小学生在蒸发、凝结和沸腾三个维度中存在的具体科学前概念内容，并对其进行类型划分，提取儿童科学前概念的基本特征；二是水平层面，从该主题的三个维度探寻小学生的概念认知水平及概念认知特点；三是原因层面，从概念认知显现出的特点深入挖掘儿童在该主题中认知的影响因素；四是发展层面，基于以上现状的研究结果，提出指向课程设计和课堂教学的具体建议。 本研究首先归纳了小学生关于“蒸发的水去处”“蒸发的条件”“凝结的水来源”“沸腾时的白气”“沸腾气泡里的物质”存在的科学前概念内容，并在此基础上分析各种科学前概念的人数占比。 其次，科学前概念是学生概念认知的结果，在概念认知水平上，我们发现小学生对该主题的概念认知水平较好，53.4%学生概念理解达到及格及以上，且学生对蒸发的概念认知优于凝结，对沸腾的概念认知依赖于对蒸发和凝结的正确认知。 再者，研究中也发现学生的年龄和性别与“水的液气相变”并没有明显的相关关系。影响学生对“水的液气相变”概念认知的关键因素是学生是否能认识到“水蒸气储存于空气中”，以及形成物质粒子观。 最后，为了进一步探析学生科学前概念的特点，我们根据已有的理论模型将小学生的科学前概念归纳为五类：第一是空壳概念，第二是条件缺失概念；第三是不完整概念；第四是异质性概念；第五是正确概念。其中43%的小学生处于前四类，在五种类型中不同年龄水平学生的概念认知具有同一性，而且随着年龄的升高，学生在第三类和第四类的科学前概念人数有所增多。基于以上研究我们认为小学生的科学前概念具有情境依赖性、矛盾性、呈现结构化体系等特征。 根据以上研究结论，我们分别针对课程设计和课堂教学提出相应的建议。在课程设计上，建议设立“儿童科学前概念内容库”和“科学前概念测量表”；根据儿童概念认知水平和概念认知路径设计课程；利用多渠道课程资源，丰富儿童概念认知。在课堂教学上，建议理解儿童科学前概念存在的意义，运用多种探测方法挖掘科学前概念；甄别儿童科学前概念类型，针对类型使用教学策略；明晰儿童科学前概念转变“关键点”，设计和实施评价策略。

Pre-scientific concept is not only the process of children’s conceptual cognition, but also the result of their conceptual cognition. It has a direct influence on children's understanding of scientific concepts, the effectiveness of science instruction and the quality of science education. The research on children's pre-scientific concept has become mature in international research of science education where the pre-scientific concept has been regarded as an important curriculum and instruction resource. However, the research on pupils' preconception in China has been relatively weak. In the study, 402 children aged 6-12 in two primary schools in Beijing were selected to explore the pre-scientific concepts of “liquid-gas change of water”. Various methods were applied, including questionnaires, mapping and event-based interviews. During the study, we firstly explored what the pre-scientific concepts children holds, divided the children’s concepts into five levels and extracted its basic traits. Secondly, from the layer perspective, we researched the level of children’s concepts and its characteristics. Thirdly, we tried to reveal in-depth factors that affect children to understand the scientific concepts in the topic. Finally, according to the result, we proposed some specific suggestions for curriculum design and instruction. In the result, this study summarized the contents of the pre-scientific concepts about “where does the water go” “how can water evaporate” “where is the water from” “what is the steam when boiling” and “what are the substances in boiling bubbles”. Then the proportions of pre-scientific concepts were analyzed. In the second part, pre-scientific concepts were the result of students' conceptual cognition. At the level of conceptual cognition, we found that pupils' conceptual understanding of the subject was good. Around 53.4% of pupils has passed the test, and their conceptual understanding on “evaporation” was better than that on “condensation”. The conceptual cognition of boiling depends on the correct understanding on evaporation and condensation. Furthermore, the study also found that the age and gender don’t have a great influence on the understanding of concepts on “liquid-gas phase change of water”. The key factors affecting students' understanding of the concepts were whether they could realize that “water vapor is stored in the air” and the form of particles. In the next part, we divided pupils' pre-scientific concepts into five categories according to the existing theoretical models: the first is empty concept, the second is the concept with conditional absence, the third is the concept with incompleteness, the fourth is the concept with heterogeneity, and the fifth is the correct concept. Among them, 43% of pupils were in the former four categories, and students at different age levels shared the same conceptual cognition. With the increase of age, the number of students in the third and fourth categories goes up. Based on the above research, we believe that pupils' pre-scientific concepts are situationally dependent, contradictory and structured. At the last part, we put forward some reasonable suggestions for curriculum design and instruction. For curriculum design, it was suggested to set up a “pre-scientific concept inventory” and a “pre-scientific concept test”; to design curriculum according to children's conceptual cognitive level and conceptual cognitive path; and to enrich children’s conceptual cognition by utilizing multi-channel curriculum resources. In classroom teaching, it was suggested to understand the significance of pre-scientific concepts from children; to explore children’s ideas by various detection methods; to identify the types of pre-scientific concepts for children matching related teaching strategies, to clarify the key points of pre-scientific concepts for children, and to design and implement evaluation strategies.