基于信息技术定量探究惯性大小的影响因素

惯性知识具有高度的抽象性和概括性,学生的抽象思维尚未成熟,对其缺乏深度的理性认识,惯性大小影响因素的教学成为了中学物理教学的难题.传统实验以物体的撞击效果衡量惯性的大小,缺少数据支撑及合理性.为解决这一问题,结合前人的理论研究,融入信息技术,采用手机、光电门计时器等器材,利用Tracker软件和Origin软件,对时间、速度改变量以及作用力三个物理量进行定量研究,最终证明影响惯性大小的因素为质量而非速度.

宽透立体正确地理解“惯性”概念

从“惯性”概念的正确内涵、物体惯性的显示表现、走出“物体速度越大惯性越大”的认识误区和物体惯性大小直接由其质量大小决定等方面来实现宽透立体正确理解“惯性”概念的目标。

Estimation of Soil Hydrodynamic Parameters Related to Agricultural Practices -Case of the Tougou Experimental Site （Burkina Faso）

This study aims to estimate the hydrodynamic properties of soils under various agricultural practices in the Tougou catchment in northern Burkina Faso. The methodology adopted is based on the determination of the unsaturated hydraulic conductivity and capillary sorptivity close to saturation. This method relies on the measurement of the transient infiltration flux at the soil surface with imposed hydraulic head varying from -60 to -20 mm. These tests are carried out on control, stony line, half-moon and zai plots. The results show a difference in hydrodynamic parameters according to the agricultural practices. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The pores participating to water transfer also differ. The mean size of drainable pores is 43.7, 56.2, 22.3 and 87.2 pm on control, stony line, half-moon and zai plots respectively.

对惯性教学的再探讨

在初中阶段学生对惯性概念认识一直比较肤浅甚至错误,这是业内广为人知的,并为此已有很多同行进行探讨过.笔者也为此困惑多年,偶然间发现现行不同版本教材在处理惯性教学内容安排上有很大的差异.为何不同版本教材在内容上有如此多的不同安排,这对学生理解惯性知识又有何影响？这引起了笔者的强烈关注,并试着对初中物理惯性教学的再次探讨.