浅议提升小学科学分组实验教学实效性的措施

科学实验是小学科学教学的重要组成部分,通过实验教学,特别是分组实验教学,可以很好地帮助学生形成科学概念,提升动手动脑能力,培养科学思维和创新精神。因此,切实提升实验教学的实效性,是小学科学课程目标得以落实的重要途径。本文以日常科学教学中几个分组实验为案例,分别从实验现象的直观性、实验器材的选择、实验过程的优化、不同学科知识的渗透四个方面,对如何提升小学科学分组实验教学的实效性,进行了一些反思,提出了一些改进意见和建议,以期对实际教学有所帮助。

在实验教学上下功夫,进一步深化实验教学改革

旨在从实验教学项目内容体系、实验教学模式及环节方面，通过专业课程的实验教学改革，进一步探讨深化实验教学改革，更好地提高实验的实效性。

回归本源,做好物理实验——浅谈物理课堂有效教学

物理是一门以观察和实验为基础的学科,许多物理知识来源于实验,实验不但是人们获取物理知识的一个重要途径,而且是帮助学生学习物理概念、规律的一个重要手段。因此,提高课堂效率,要注重物理实验的操作的实效性。

Design and preliminary experimental investigation of a 4K Stirling-type pulse tube cryocooler with precooling

A Stirling-type pulse tube cryocooler （PTC） with precooling was designed and manufactured to investigate its performance at 4 K. Numerical simulation was carried out based on the well-known regenerator model REGEN with an emphasis on the performance of a 4 K stage regenerator of the Stifling-type PTC as influenced by the warm end temperature, pressure ratio, frequency and average pressure with helium-4 and helium-3 as the working fluid respectively. This study demonstrates that the use of a cold inertance tube can significantly improve the efficiency of a 4 K Stirling-type PTC. A preliminary experimental investigation was carried out with helium-4 as the working fluid and a refrigeration temperature of 4.23 K was achieved. The experimental results show that the operating frequency has a significant influence on the performance of the Stirling-type PTC and a relatively low average pressure is favorable for decreasing the loss associated with the real gas effects of a 4 K Stirling-type PTC.