[评析]“角的度量”课例点评

1、评析“角的度量”课例点评“角的度量”是在学生认识角的大小的基础上进行的，是学生今后学习画角和三角形分类的基础，又是小学阶段几何初步知识的一个重要内容。本节课的教学设计，本着“发展学生为主”的原则，引导他们通过主动动手操作、观察比较，大胆表达，从中进行数学思维方法的渗透和有效的学习方法指导；引导他们在主动的探索中了解角的度量工具、计量单位以及掌握量角器的使用方法，并培养学生乐学、善学和会学。1.创设情境，提出问题。面向21世纪的小学数学教育，着重于“促进学生解决问题的能力和创造力”，要求之一是能从日常生活和数学内容中找数学问题，能发展和应用各种策略去解决问题。在课的开始教师出示图问角的大小与什么

2、有关？如何测量。学生无从说出如何测量叫的大小，这就引起学生认知上的冲突，促使学生产生积极探究未知的心理倾向，从而在激发学生学习求知欲的基础上，明确学习内容和目标；并揭示课题。2.主动探索，学会学习。（1）师生合作，导探理法。在认识量角器的学习中，教师有意识地指导学生学会观察对比，从中把握量角器的共同特征，并恰到好处地渗透“透过事物的表象，从而准确地把握事物的特征”的思想。在观察量角器的过程中，教师让学生充分质疑，并创造条件让学生自行解疑。如动手实践后发现内、外刻度的作用，并感受到量角器设计的科学性，促进学生养咸动脑筋、善思考的习惯。在学生对量角器充分认识的基础上，教师又再次放手让学生自己通过小

3、组合作学习， 自行探索并归纳出度量角度的三步骤，并学会抓住关键字眼，理解记忆。（2）合作学习，深探用法。在掌握量法后，教师引导学生进一步运用学到的知识，解决量法的具体应用问题。让学生在小组合作学习中，又一次动手运用量法进行实验、观察对比，从中发现角的大小变化的规律，并能自觉地运用已发现的规律，解决角的两边画得太短而不好量的困难，并不失时机地发展学生的求异思维，让他们各抒己见，充分发表自己不同的解决问题的方法，使全班学生的认识都有不同水平的提高。学会角的度量后，教师还设计让学生考察眼力，先估算三角形各角的度数，后动手测量加以验证。这不仅巩固量法，还进一步发展学生对角度的空间想象力和估算能力。总之

4、，这节课的教学设计中，立足把学习的主动权交给学生，课堂始终为学生提供了大量的动手操作、观察对比、自主探索的机会和成功的机会。在知识形成的过程中不断提出问题和解决问题，并进行学法指导，使学生的潜能得到较好的发挥，学生的实践能力与创新精神都得到较好的培养。 tgz7r4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgshls50clmtwn60eo8wgqv7xav2ohum32wgeauwydiawgmer4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgz7r4i30ka1dkagtgk tgz

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