一、将模糊变清晰 如《物体的热涨冷缩》一课,关于空气的热胀冷缩实验:在烧瓶口中堵一个插着玻璃管的塞子,在管里滴一滴带颜色的水,外面用线做个标记,然后用热毛巾捂住玻璃瓶,瓶内空气逐渐变热,管里的小水滴就会向管口移动,放开热毛巾,瓶里空气变冷,管里的小水滴向相反方向移动。这个实验可见度小,且移动距离短,搞不好小水滴会 First, the blur becomes clear, such as “the object of hot up and cold shrinking” lesson, on the air thermal expansion and contraction experiment: plug in the mouth of a flask plugged glass tube, a drop of colored water in the tube, outside Marked with a line, and then covered with a hot towel glass bottle, the bottle gradually become hot air, the tube of water droplets will move to the nozzle, let go of the hot towel, cold air bottle, the tube of water droplets Move in the opposite direction. Visibility of this experiment is small, and the moving distance is short, engage in small droplets will be