基于學(xué)生基礎(chǔ)有效教學(xué)

喻伯軍

在日常教學(xué)中，有些教師只按照教材進(jìn)行教學(xué)，而忽略了學(xué)生的基礎(chǔ)，導(dǎo)致教學(xué)的針對(duì)性和有效性大為降低，也沒有激發(fā)出學(xué)生的興趣。如一年級(jí)數(shù)學(xué)課中“1～5的認(rèn)識(shí)”，“磁鐵”單元學(xué)生對(duì)磁鐵吸引鐵的物品等性質(zhì)的認(rèn)識(shí)，學(xué)生的經(jīng)驗(yàn)已經(jīng)非常豐富了，而教師還是當(dāng)作學(xué)生不知道，使學(xué)生的學(xué)習(xí)在原來基礎(chǔ)上重復(fù)了一遍。

學(xué)生進(jìn)入學(xué)校學(xué)習(xí)時(shí)，腦中并不是“一張白紙”，他們有自己的經(jīng)驗(yàn)和一些初始認(rèn)識(shí)，這些已有的認(rèn)識(shí)和經(jīng)驗(yàn)，會(huì)影響他們對(duì)新知識(shí)的接受。心理學(xué)研究表明，新知識(shí)的學(xué)習(xí)只有納入學(xué)生已有的認(rèn)知結(jié)構(gòu)后，才會(huì)很好地被學(xué)生理解和掌握，因此教師的教學(xué)應(yīng)該遵循這樣的規(guī)律。關(guān)于這個(gè)觀點(diǎn)，美國(guó)著名的教育心理學(xué)家奧蘇伯爾在他1978年出版的《教育心理學(xué)：認(rèn)知觀》一書的扉頁寫道：“假如讓我把全部教育心理學(xué)僅僅歸納為一條原理的話，那么，我將一言以蔽之曰：影響學(xué)生唯一最重要的因素就是學(xué)生已經(jīng)知道什么，要探明這一點(diǎn)，并應(yīng)據(jù)此進(jìn)行教學(xué)。”

小學(xué)生學(xué)習(xí)科學(xué)的基礎(chǔ)包括知識(shí)基礎(chǔ)（科學(xué)前概念）、能力基礎(chǔ)、學(xué)習(xí)習(xí)慣和態(tài)度、學(xué)習(xí)心理與價(jià)值觀等。教師要想取得良好的教學(xué)效果，就必須清楚一定年齡段的學(xué)生已經(jīng)知道了什么，懂得些什么，具備了怎樣的能力，會(huì)做些什么；必須清楚哪些方面學(xué)生會(huì)學(xué)得很快，哪些方面學(xué)起來比較困難等。教師不僅要預(yù)見學(xué)生容易誤解的地方，也需要判斷知識(shí)的難易程度是否適合學(xué)生的發(fā)展水平。在此基礎(chǔ)上，及時(shí)調(diào)整教學(xué)目標(biāo)，針對(duì)性地設(shè)計(jì)教學(xué)內(nèi)容，采取相應(yīng)的教學(xué)手段。

學(xué)習(xí)使用酒精燈是常規(guī)的技能要求。課堂現(xiàn)實(shí)是，當(dāng)學(xué)生要學(xué)習(xí)用酒精燈加熱的活動(dòng)時(shí)，大部分學(xué)生甚至不會(huì)劃火柴，一些學(xué)生好不容易劃著了火柴，又嚇得立即扔掉。針對(duì)這種現(xiàn)象，某教師及時(shí)調(diào)整了教學(xué)內(nèi)容和策略：先學(xué)習(xí)劃火柴和觀察火焰，再學(xué)習(xí)用酒精燈加熱。教師先演示怎樣劃火柴，把劃著的火柴平放，觀察火柴的火焰分層，讓學(xué)生消除緊張情緒。等到學(xué)生熟悉了點(diǎn)火，消除了對(duì)火焰的恐懼之后，再繼續(xù)學(xué)習(xí)教材上的內(nèi)容。經(jīng)過調(diào)整，這節(jié)課得以順利地進(jìn)行，并且收到了很好的效果。

“小車的運(yùn)動(dòng)”這個(gè)內(nèi)容中，學(xué)生在探究小車運(yùn)動(dòng)與拉力大小的關(guān)系時(shí)，教師發(fā)現(xiàn)學(xué)生其實(shí)都知道拉力越大小車運(yùn)動(dòng)越快的結(jié)論，因?yàn)檫@是學(xué)生的常識(shí)，所以這個(gè)活動(dòng)對(duì)學(xué)生的吸引力不大，學(xué)習(xí)的價(jià)值也就降低了。針對(duì)這個(gè)現(xiàn)象，如何讓學(xué)生在活動(dòng)中更有興趣并深入思維？教師可以借鑒項(xiàng)目式學(xué)習(xí)的要素，把驅(qū)動(dòng)性的問題調(diào)整為：如何讓小車精準(zhǔn)到達(dá)某個(gè)區(qū)域。讓學(xué)生去解決問題，成功地激發(fā)了學(xué)生的探究欲望，使得他們學(xué)習(xí)積極性高漲，學(xué)習(xí)的效果大大超出了教師的預(yù)期。

學(xué)生學(xué)習(xí)的起點(diǎn)是先前已有的知識(shí)、經(jīng)驗(yàn)、能力等，終點(diǎn)是社會(huì)期望，中間有許多不同的發(fā)展水平。如何在教學(xué)中達(dá)到針對(duì)性的教學(xué)和高效的結(jié)果，這是每一個(gè)教師都應(yīng)該思考的問題。在教學(xué)前，教師要根據(jù)教材內(nèi)容和學(xué)生實(shí)際情況，制定恰當(dāng)?shù)慕虒W(xué)目標(biāo)；在教學(xué)中，教師要根據(jù)學(xué)生的反應(yīng)和課堂教學(xué)的具體情況，及時(shí)調(diào)整教學(xué)內(nèi)容和方法，確保更好地實(shí)現(xiàn)教學(xué)目標(biāo)；在教學(xué)后，教師要反思自己的教學(xué)手段是否適合學(xué)生的學(xué)習(xí)，以便及時(shí)改進(jìn)。

教師關(guān)注學(xué)生的基礎(chǔ)，還包括關(guān)注他們是如何思考的，他們的觀點(diǎn)是如何形成的，錯(cuò)誤概念是如何改變的，正確的觀念又是如何建立的，從而在教學(xué)中選擇學(xué)生易于接受的學(xué)習(xí)路徑，建立新的學(xué)習(xí)范式。

Effective Teaching Based on Students’ Basic Knowledge

YU Bojun

中圖分類號(hào)：G424文獻(xiàn)標(biāo)識(shí)碼：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.