【教材分析】本课是“热”单元中的第四课,在研究液体的热胀冷缩后,让学生研究空气的热胀冷缩,空气是肉眼看不见的,需要借助其他的物体变化而间接地观察体积的变化,教材要求让学生自主思考、设计观察方法。观察空气的热胀冷缩现象后,学生对空气和水的热胀冷缩做比较,进而尝试着对水和空气的热胀冷缩给出解释,学生通过小游戏:模拟空气“微粒”的运动,了解热胀冷缩的原因。【学情分析】学生已经研究过液体的热胀冷缩, 【Textbook analysis】 This lesson is “hot ” unit in the fourth lesson, after studying the thermal expansion and contraction of liquid, let students study the thermal expansion and contraction of air, the air is invisible to the naked eye, need to use other Changes in objects and indirectly observe changes in volume, textbooks require students to think independently, design observation methods. After observing the phenomenon of thermal expansion and contraction of air, students compare the thermal expansion and contraction of air and water, and then try to explain the thermal expansion and contraction of water and air. Through the mini-game: "Movement, understand the reasons for thermal expansion and contraction. [Analysis] students have studied the thermal expansion and contraction of liquid,