初中生理解二次函数存在问题的课堂志研究——以杜郎口中学为例

A Classroom Ethnography Study on Junior High School Students’ Problem in Understanding Quadratic Function:Taking Dulangkou Middle School as an Example

文章采用课堂志的研究方法对杜郎口中学九年级一节二次函数应用的数学课展开研究。研究发现学生对二次函数的理解存在的问题有:学生区分不开二次函数和一元二次方程,学生无法准确确定自变量的取值范围,学生将实际问题转化成数学问题差。学生出现这些问题的主要原因是概念不清、思维方式单一及想象力较薄弱。教师在教学中要重点强调二次函数和一元二次方程的区别,多使用图像辅助学生思考,并为学生提供相关问题情境。

This paper adopts the classroom ethnography method to study a math class of quadratic function in the ninth grade of Dulangkou Middle School.It is found that there are some problems in students’understanding of quadratic function:1)being unable to distinguish between quadratic equation and unary quadratic equation,2)being unableto accurately determine the value range of independent variables,and 3)being unableto turn practical problems into mathematical questions.Main reasons for these problems include students’inadequate understanding of concepts,single mode of thinking,and poor imagination.Teachers thus should emphasize the difference between quadratic function and unary quadratic equation,use more pictures to help students think,and givepractical situations for mathematical problems.