[評析]“角的度量”課例點(diǎn)評

1、評析“角的度量”課例點(diǎn)評“角的度量”是在學(xué)生認(rèn)識(shí)角的大小的基礎(chǔ)上進(jìn)行的，是學(xué)生今后學(xué)習(xí)畫角和三角形分類的基礎(chǔ)，又是小學(xué)階段幾何初步知識(shí)的一個(gè)重要內(nèi)容。本節(jié)課的教學(xué)設(shè)計(jì)，本著“發(fā)展學(xué)生為主”的原則，引導(dǎo)他們通過主動(dòng)動(dòng)手操作、觀察比較，大膽表達(dá)，從中進(jìn)行數(shù)學(xué)思維方法的滲透和有效的學(xué)習(xí)方法指導(dǎo)；引導(dǎo)他們在主動(dòng)的探索中了解角的度量工具、計(jì)量單位以及掌握量角器的使用方法，并培養(yǎng)學(xué)生樂學(xué)、善學(xué)和會(huì)學(xué)。1.創(chuàng)設(shè)情境，提出問題。面向21世紀(jì)的小學(xué)數(shù)學(xué)教育，著重于“促進(jìn)學(xué)生解決問題的能力和創(chuàng)造力”，要求之一是能從日常生活和數(shù)學(xué)內(nèi)容中找數(shù)學(xué)問題，能發(fā)展和應(yīng)用各種策略去解決問題。在課的開始教師出示圖問角的大小與什么

2、有關(guān)？如何測量。學(xué)生無從說出如何測量叫的大小，這就引起學(xué)生認(rèn)知上的沖突，促使學(xué)生產(chǎn)生積極探究未知的心理傾向，從而在激發(fā)學(xué)生學(xué)習(xí)求知欲的基礎(chǔ)上，明確學(xué)習(xí)內(nèi)容和目標(biāo)；并揭示課題。2.主動(dòng)探索，學(xué)會(huì)學(xué)習(xí)。（1）師生合作，導(dǎo)探理法。在認(rèn)識(shí)量角器的學(xué)習(xí)中，教師有意識(shí)地指導(dǎo)學(xué)生學(xué)會(huì)觀察對比，從中把握量角器的共同特征，并恰到好處地滲透“透過事物的表象，從而準(zhǔn)確地把握事物的特征”的思想。在觀察量角器的過程中，教師讓學(xué)生充分質(zhì)疑，并創(chuàng)造條件讓學(xué)生自行解疑。如動(dòng)手實(shí)踐后發(fā)現(xiàn)內(nèi)、外刻度的作用，并感受到量角器設(shè)計(jì)的科學(xué)性，促進(jìn)學(xué)生養(yǎng)咸動(dòng)腦筋、善思考的習(xí)慣。在學(xué)生對量角器充分認(rèn)識(shí)的基礎(chǔ)上，教師又再次放手讓學(xué)生自己通過小

3、組合作學(xué)習(xí)， 自行探索并歸納出度量角度的三步驟，并學(xué)會(huì)抓住關(guān)鍵字眼，理解記憶。（2）合作學(xué)習(xí)，深探用法。在掌握量法后，教師引導(dǎo)學(xué)生進(jìn)一步運(yùn)用學(xué)到的知識(shí)，解決量法的具體應(yīng)用問題。讓學(xué)生在小組合作學(xué)習(xí)中，又一次動(dòng)手運(yùn)用量法進(jìn)行實(shí)驗(yàn)、觀察對比，從中發(fā)現(xiàn)角的大小變化的規(guī)律，并能自覺地運(yùn)用已發(fā)現(xiàn)的規(guī)律，解決角的兩邊畫得太短而不好量的困難，并不失時(shí)機(jī)地發(fā)展學(xué)生的求異思維，讓他們各抒己見，充分發(fā)表自己不同的解決問題的方法，使全班學(xué)生的認(rèn)識(shí)都有不同水平的提高。學(xué)會(huì)角的度量后，教師還設(shè)計(jì)讓學(xué)生考察眼力，先估算三角形各角的度數(shù)，后動(dòng)手測量加以驗(yàn)證。這不僅鞏固量法，還進(jìn)一步發(fā)展學(xué)生對角度的空間想象力和估算能力?？傊?/p>

4、，這節(jié)課的教學(xué)設(shè)計(jì)中，立足把學(xué)習(xí)的主動(dòng)權(quán)交給學(xué)生，課堂始終為學(xué)生提供了大量的動(dòng)手操作、觀察對比、自主探索的機(jī)會(huì)和成功的機(jī)會(huì)。在知識(shí)形成的過程中不斷提出問題和解決問題，并進(jìn)行學(xué)法指導(dǎo)，使學(xué)生的潛能得到較好的發(fā)揮，學(xué)生的實(shí)踐能力與創(chuàng)新精神都得到較好的培養(yǎng)。 tgz7r4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgshls50clmtwn60eo8wgqv7xav2ohum32wgeauwydiawgmer4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgz7r4i30ka1dkagtgk tgz

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