小学《自然》第一册《热胀冷缩》一课中讲了固体的热胀冷缩现象。由于固体的热胀冷缩现象不十分明显,学生用肉眼很难观察。教师用书上介绍的铜球通过铜环的实验演示的难度较大,主要是铜环和铜球的制作要求高,不加热能通过,加热后不能通过的尺寸较难把握。一般的小学,特别是农村小学,很难找到这样的铜球和铜环。鉴于这几个原因,我在教学中,设计了一个类似实验,取得了好的效果。 Elementary “Nature” Volume I “thermal expansion and contraction” a lesson about the phenomenon of solid thermal expansion and contraction. Due to the solid thermal expansion and contraction phenomenon is not very obvious, students with the naked eye is difficult to observe. The copper balls introduced by teachers in the book are more difficult to demonstrate through experimental experiments of copper rings. The main requirements of copper ring and copper ball are high production requirements, no heating can pass, and the size that can not be passed after heating is more difficult to grasp. General primary schools, especially rural primary schools, it is difficult to find such a copper ball and copper ring. For these reasons, I designed a similar experiment in teaching, and achieved good results.