经全国中小学教材审定委员会2002年审查通过的全日制普通高级中学教科书(必修加选修)《化学》第三册第二单元第一节中安排了胶体渗析的演示实验。这个实验看似简单,其实存在两个小问题:一是作为半透膜袋的材料不易制得或需花一定成本购买。如要取得完整的鸡蛋壳膜是比较难的,而胶棉薄膜或玻璃纸则是需要一定的成本来购买的。二是在操作上比较麻烦。如鸡蛋壳膜由于表面很滑,口又小,往其中加入液体时很不方便,最后还要用一根绳子把口系住,显然比较麻烦。胶棉薄膜和玻璃纸等也存在加液体和系绳子不方便两个缺点,除非买的成品就是做好的袋 The demonstration experiment of colloid dialysis was arranged in the first section of the second unit of the third volume of the third volume of chemistry, which was reviewed and approved in 2002 by the national textbook examination and approval committee for full-time ordinary high school (compulsory and optional). This experiment seems to be simple. There are actually two minor problems: First, the material used as a semipermeable membrane bag is not easy to obtain or must be purchased at a certain cost. It is difficult to obtain a complete egg shell membrane, and the glue cotton film or cellophane requires a certain cost to purchase. The second is more troublesome in operation. For example, egg shell membrane is very inconvenient because of the slippery surface and small mouth. It is very inconvenient to add liquid to it. Finally, it is necessary to tie the mouth with a rope, which is obviously troublesome. Cotton wool film and cellophane also have two disadvantages of adding liquid and inconvenient rope, unless the finished product is a good bag.