现行初中物理课本第二册第二章中水的对流演示实验,是一个比较难做的实验。其主要原因在于烧瓶内的高锰酸钾容易溶解,实验中往往来不及看清楚实验现象,整瓶水都变成了紫红色的高锰酸钾溶液了。有一些教师对该实验进行了改进。如:使用橡胶粒来代替高锰酸钾;使用铝箔和甘油来代替高锰酸钾和水;采用冷水热水对流等等。我们所设计的“水的对流演示仪”,较好地解决了演示中的一些问题。现介绍如下。演示仪包括500ml烧怀一只,无色可乐瓶一个,内 The convection demonstration experiment of water in the second chapter of the current junior middle school physics textbook is a more difficult experiment. The main reason for this is that the potassium permanganate in the flask is easily dissolved, and the experiment is often too late to see the experimental phenomenon. The whole bottle of water turns into a purple-red potassium permanganate solution. Some teachers improved the experiment. Such as: the use of rubber particles instead of potassium permanganate; the use of aluminum foil and glycerin instead of potassium permanganate and water; using cold water and hot water convection and so on. The “Water Convection Demonstration Instrument” designed by us has solved some problems in the demonstration. The introduction is as follows. The demonstration instrument includes one 500ml beaker and one colorless coke bottle inside