张军霞

我們倡导要提高课堂教学的有效性，实现学生课堂教学的真正获得。对于科学课堂教学，我们可以从微观层面上组织课堂教学的具体内容，厘清课堂教学的主线。对于教学目标中包含课程标准要求的某一学习目标的科学课堂来说，可以按照学生理解这一学习目标的由浅入深的发展路径组织学习内容，实现一堂课的概念进阶。课程标准中的各水平级学习目标，可以理解为由某一主要概念分解的水平级概念。在40分钟的课堂上理解一个水平级概念，可以参考《基于核心素养学习进阶的科学教学设计》一文中用于较短时间内具体科学概念的学习进阶的“科学概念理解的发展层级模型”（以下简称层级模型）进行设计。

层级模型将对概念理解的发展路径分为经验、映射、关联、系统和整合五个层级。这五个层级的概念理解程度可以这样理解：经验，学生具有一些没有产生相互关联的日常经验和零散事实；映射，学生能够建立概念与经验之间的关系；关联，学生能够建立概念与多个经验特征之间的关系；系统，学生能够建构对科学概念的基本理解；整合，学生能够在更广泛的情境中应用概念，表现出具有一定的科学观念，或跨学科解决问题的能力。

例如，二年级《把它们放进水里》一课，设定的重点教学目标对应课程标准中的1～2年级学习目标：知道有些物体能够溶解在一定量的水中，如食盐和白糖等；有些物质很难溶解在水里，如沙和食用油等。按照层级模型的发展路径开展教学，能够使学生在一堂课中初步建构这一概念。

经验：出示白砂糖、酸梅晶（或红糖）、木屑、沙子等一些易溶解和难溶解的固体物质，让学生预测这些物质放入水中会怎样，获得学生对溶解的原有认识。

映射：将这些固体物质放入水中，获得对溶解的最初认识——固体看不见了。

关联：将酸梅晶放入水中，观察酸梅晶放入水中的过程，获得对溶解的初步认识——固体均匀分散在水中。将食用油、蜂蜜等液体物质放入水中，获得对溶解的初步认识：液体也能均匀分散在水中。

系统：通过对上述现象的归纳，初步概括什么是溶解——物质均匀分散在水中，看不见了。

整合：在本节课即将结束之时，将许多盐倒入少量水中，获得指向主要概念的科学认识——物质在水中溶解的量受到水量的限制，即物质溶解在一定量的水里。

如果教学目标包含的科学概念有多重含义，在应用层级模型进行教学设计时，五个层级可以交错进行。

例如，三年级《食物的消化》一课，设定的重点教学目标对应课程标准中的3～4年级学习目标：简要描述人体用于摄取养分的器官。本课教学对消化器官的认识，要与食物进入人体被消化的路径结合起来。

经验1：在口腔里咀嚼馒头，体会咀嚼过的馒头在牙齿、舌头、唾液作用下，变小了、黏了、甜了。

映射1：用碘酒检查咀嚼过和没有咀嚼过的馒头，体会馒头的初步消化——部分淀粉变为糖。

关联：吃入冰镇的水果，体会食物由口腔进入消化器官的上部路径——食物从口腔经食道进入胃。

经验2：画食物路径图，了解学生对消化器官的已有认知。

映射2：观察消化器官立体图，初步认识消化器官。

系统：观看介绍消化器官的视频资料，综合以上教学经验，学生可以认识食物在经过消化器官的过程中逐渐被消化、吸收的基本过程。

整合：如果还有教学时间，本课最后可以引导学生学习如何保护消化器官。

以上探讨的都是以建构科学概念为重点教学目标的课例。不以建构科学概念为主的其他科学课堂，如属于技术与工程领域的设计、制作、评估、改进等课，需要结合设计思维与工程思维设计教学。

Strive to Realize the Concept Advancement of a Class

ZHANG Junxia

中图分类号：G424文献标识码：ADOI：10.16400/j.cnki.kjdk.2021.05.001

ZHANG Junxia

Deputy Director （in charge of work） and Editor of Comprehensive Science Department of People’s Education Press

Member of the Textbook Compilation Group of Science Published by People’s Education Hubei Education Press

Deputy Secretary General of Science Popularization Education Committee of China Science Popularization Writers Association

We advocate improving the effectiveness of class？ room teaching and realizing the real acquisition of students’ classroomteaching. For scienceclassroom teaching，wecanorganizethespecificcontentof classroom teaching from the micro level and clarify the main line of classroom teaching. For the science classroom whose teaching objectives include a certain learning objective required by the curriculumstan？ dard， we can organize the learning content according to the development path of students’ understanding of this learning objective， and realize the concept ad？ vancement of a class. The learning objectives of each level in the curriculum standard can be understood as the level concept decomposed by a main concept. Tounderstandalevelconceptinthe40-minute class， we can refer to the "hierarchical model for the developmentofscientificconceptunderstanding"（hereinafter referred to as the hierarchical model） in the article "advanced science teaching design based oncoreliteracylearning"，whichisusedforthe learning of specific scientific concepts in a short time.

The hierarchical model divides the development path of concept understanding into five levels： experi？ ence，mapping，relevance，systemandintegration. These five levels of conceptual understanding can be understood as follows： experience， students have some daily experience and scattered facts that are not relat？ ed to each other； Mapping， students can establish the relationshipbetweenconceptandexperience；Rele？ vance， students can establish the relationship between concepts and multiple experience characteristics； Sys？ tem， students can construct the basic understanding ofscientificconcepts；Throughintegration，students can apply concepts in a wider range of situations and show a certain scientific concept or interdisciplin？ ary problem-solving ability.

For example， in the second grade lesson "put them in the water"， the key teaching objectives set correspond to the learning objectives of grade 1-2 in the curriculum standard： know that some objects can be dissolved in a certain amount of water， such as salt and sugar， etc； Some substances are difficult to dissolve in water， such as sand and edible oil. Ac？ cording to the development path of hierarchical mod？ el， students can construct this concept in a class.

Experience： show some soluble and insoluble sol？ id substances， such as white granulated sugar， sour plum crystal （or brown sugar）， sawdust， sand， etc.， andaskstudentstopredicthowthesesubstances will be put into water， so as to obtain students’ origi？ nal understanding of dissolution.

Mapping： put these solids in water to get the first idea of dissolution - the solids are out of sight.

Relevance： put sour plum crystal into water， ob？ serve the process of putting sour plum crystal into water， and get a preliminary understanding of dissolu？ tion - solid is evenly dispersed in water. Put edible oil， honey and other liquid substances into water to get a preliminary understanding of dissolution： liquid can also be evenly dispersed in water.

System： through the induction of the above phe？ nomena， we can preliminarily summarize what is dis？ solution - the matter is evenly dispersed in water and cannot be seen.

Integration： at the end of this lesson， pour a lot of salt into a small amount of water to get a scientif？ icunderstandingofthemainconceptthatthe amount of matter dissolved in water is limited by the amount of water， that is， matter dissolved in a cer？ tain amount of water.

If the scientific concepts contained in the teach？ ing objectives have multiple meanings， the five levels can be staggered when applying the hierarchical mod？ el to the teaching design.

For example， in the third grade of "food diges？ tion"， the key teaching goal set corresponds to the learning goal of grade 3-4 in the curriculum stan？ dard： briefly describe the organs used by the human body to absorb nutrients. The understanding of diges？ tive organs in this course should be combined with the path of food entering the human body and being digested.

Experience1：chewingsteamedbreadinthe mouth，experiencechewingsteamedbreadinthe teeth， tongue， saliva， smaller， sticky， sweet.

Mapping1：checksteamedbreadchewedand not chewed with iodine wine， and experience the ini？ tial digestionof steamedbread--part of starch turns into sugar.

Relevance： eating iced fruit， experience the up？ per path of food from the mouth to the digestive or？ gans - food from the mouth through the esophagus into the stomach.

Experience 2： draw food path map to understand students’ cognition of digestive organs.

Mapping 2： observe the stereogram of digestive organs to get a preliminary understanding of digestive organs.

System： by watching the video materials about di？ gestive organs and integrating the above teaching ex？ perience， students can understand the basic process that food is gradually digested and absorbed in the process of passing through digestive organs.

Integration： if there is still teaching time， this lesson can guide students to learn how to protect di？ gestive organs.

The above discussion is based on the construc？ tion of scientific concepts as the focus of teaching ob？ jectives. Other science classes that do not focus on the construction of scientific concepts， such as de？ sign， production， evaluation and improvement in the field of technology and engineering， need to combine design thinking with engineering thinking.