喻伯军

在日常教學中，有些教师只按照教材进行教学，而忽略了学生的基础，导致教学的针对性和有效性大为降低，也没有激发出学生的兴趣。如一年级数学课中“1～5的认识”，“磁铁”单元学生对磁铁吸引铁的物品等性质的认识，学生的经验已经非常丰富了，而教师还是当作学生不知道，使学生的学习在原来基础上重复了一遍。

学生进入学校学习时，脑中并不是“一张白纸”，他们有自己的经验和一些初始认识，这些已有的认识和经验，会影响他们对新知识的接受。心理学研究表明，新知识的学习只有纳入学生已有的认知结构后，才会很好地被学生理解和掌握，因此教师的教学应该遵循这样的规律。关于这个观点，美国著名的教育心理学家奥苏伯尔在他1978年出版的《教育心理学：认知观》一书的扉页写道：“假如让我把全部教育心理学仅仅归纳为一条原理的话，那么，我将一言以蔽之曰：影响学生唯一最重要的因素就是学生已经知道什么，要探明这一点，并应据此进行教学。”

小学生学习科学的基础包括知识基础（科学前概念）、能力基础、学习习惯和态度、学习心理与价值观等。教师要想取得良好的教学效果，就必须清楚一定年龄段的学生已经知道了什么，懂得些什么，具备了怎样的能力，会做些什么；必须清楚哪些方面学生会学得很快，哪些方面学起来比较困难等。教师不仅要预见学生容易误解的地方，也需要判断知识的难易程度是否适合学生的发展水平。在此基础上，及时调整教学目标，针对性地设计教学内容，采取相应的教学手段。

学习使用酒精灯是常规的技能要求。课堂现实是，当学生要学习用酒精灯加热的活动时，大部分学生甚至不会划火柴，一些学生好不容易划着了火柴，又吓得立即扔掉。针对这种现象，某教师及时调整了教学内容和策略：先学习划火柴和观察火焰，再学习用酒精灯加热。教师先演示怎样划火柴，把划着的火柴平放，观察火柴的火焰分层，让学生消除紧张情绪。等到学生熟悉了点火，消除了对火焰的恐惧之后，再继续学习教材上的内容。经过调整，这节课得以顺利地进行，并且收到了很好的效果。

“小车的运动”这个内容中，学生在探究小车运动与拉力大小的关系时，教师发现学生其实都知道拉力越大小车运动越快的结论，因为这是学生的常识，所以这个活动对学生的吸引力不大，学习的价值也就降低了。针对这个现象，如何让学生在活动中更有兴趣并深入思维？教师可以借鉴项目式学习的要素，把驱动性的问题调整为：如何让小车精准到达某个区域。让学生去解决问题，成功地激发了学生的探究欲望，使得他们学习积极性高涨，学习的效果大大超出了教师的预期。

学生学习的起点是先前已有的知识、经验、能力等，终点是社会期望，中间有许多不同的发展水平。如何在教学中达到针对性的教学和高效的结果，这是每一个教师都应该思考的问题。在教学前，教师要根据教材内容和学生实际情况，制定恰当的教学目标；在教学中，教师要根据学生的反应和课堂教学的具体情况，及时调整教学内容和方法，确保更好地实现教学目标；在教学后，教师要反思自己的教学手段是否适合学生的学习，以便及时改进。

教师关注学生的基础，还包括关注他们是如何思考的，他们的观点是如何形成的，错误概念是如何改变的，正确的观念又是如何建立的，从而在教学中选择学生易于接受的学习路径，建立新的学习范式。

Effective Teaching Based on Students’ Basic Knowledge

YU Bojun

中图分类号：G424文献标识码：ADOI：10.16400/j.cnki.kjdk.2021.18.002

YU Bojun

Deputy Director of Zhejiang Provincial Teaching and Research Office

Primary School Science Teacher

Core Member of Science Curriculum Standard Revision Group of Ministry of Education

In the daily teaching， some teachers only teach according to the teaching materials， but ignore the ba？ sis of students， which leads to the reduction of the pertinenceandeffectivenessofteaching，anddoes not stimulate the interest of students. For example， in the first grade mathematics class， "understanding of 1 ～ 5"， "magnet" unit， the students’ understand？ ing of the nature of magnets attracting iron objects has been very rich， but the teacher still regards the students as not knowing， so that the students’ learn？ ing is repeated on the original basis.

When students enter school， their mind is not"a blank sheet". They have their own experience and some initial knowledge， which will affect their accep？ tanceofnewknowledge.Psychologicalresearch shows that the learning of new knowledge can only be well understood and mastered by students after it is incorporated into their existing cognitive structure. Therefore， teachers should follow this rule in teach？ ing. On this point of view， Ausubel， a famous Ameri？ can educational psychologist， wrote on the front page of his bookEducational Psychology： cognitive view published in 1978： "if I summarize all educational psychology into one principle， then I will say in a word： the only and most important factor affecting stu？ dentsiswhat theyalreadyknow. Toexplorethis point， and teaching should be carried out according？ ly. "

The basis of primary school students’ learning science includes knowledge basis （pre scientific con？ cept），abilitybasis，learninghabitsandattitudes， learning psychology and values， etc. If teachers want to achieve good teaching effect， they must know what studentsofacertainagehaveknown，whatthey know， what abilities they have and what they will do； It is necessary to know which aspects students will learn quickly and which aspects are difficult to learn. Teachers should not only foresee where stu？ dentsareeasytomisunderstand，butalsojudge whether the difficulty of knowledge is suitable for stu？ dents’ development level. On this basis， adjust the teaching objectives in time， design the teaching con？ tent pertinently and adopt the corresponding teaching means.

Learning to use alcohol lamp is a routine skill requirement.Therealityoftheclassroomisthat when students want to learn to use alcohol lamp to heat the activity， most of them can’t even strike a match. Some students can’t easily strike a match and are scared to throw it away immediately. In view of this phenomenon， a teacher timely adjusted the teach？ ing content and strategy： first learn to strike matches and observe the flame， and then learn to use alcohol lamp heating. First， the teacher demonstrates how to strike a match. Put the striking match flat and ob？ serve the flame stratification of the match. Let the students get rid of the tension. When the students are familiar with the ignition， eliminate the fear of fire， and then continue to learn the content of the textbook. After adjustment， this class can be carried out smoothly， and received good results.

Inthecontent of "carmovement"， whenstu？ dents explore the relationship between car movement and pulling force， the teacher finds that students all know that the bigger the pulling force is， the faster the car movement is. Because this is students’ com？ mon sense， this activity is not attractive to students， and the value of learning is reduced. In view of this phenomenon， how to make students more interested inactivitiesandin-depththinking？Teacherscan learnfromtheelementsofproject-basedlearning， and adjust the driving problem to： how to make the car accurately reach a certain area. Let the students to solve the problem， successfully stimulate the stu？ dents’ desire to explore， make their learning enthusi？ asm rise， the effect of learning greatly exceeds the teacher’s expectation.

The starting point of students’ learning is the previous knowledge， experience， ability， etc.， and the end point is the social expectation. There are many different levels of development in the middle. How to achievetargetedteachingandefficientresultsin teaching is a problem that every teacher should think about. Before teaching， teachers should formulate ap？ propriate teaching objectives according to the content of teaching materials and the actual situation of stu？ dents； In teaching， teachers should adjust the teach？ ing contents and methods in time according to the students’ reaction and the specific situation of class？ room teaching， so as to ensure the better realization of teaching objectives； After teaching， teachers should reflect on whether their teaching methods are suitable for students’ learning， so as to improve in time.

Teachers pay attention to the basis of students， includinghowtheythink，howtheirviewsare formed， how wrong concepts are changed， and how correct concepts are established， so as to choose the learningpaththatstudentsareeasytoacceptin teaching and establish a new learning paradigm.