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渗透吸水是高中生物课中很难达到实验效果的演示实验,主要原因是难以找到适宜的半透膜材料。鱼鳔、猪膀胱、肠衣等都太厚,所以渗透装置的漏斗管内水柱上升不显著;鸡蛋壳膜很薄,但容易弄破,不可能将它封在漏斗口作并透膜。经过多次摸索,我找到了一种较好的利用鸡蛋壳膜的方法。 取新鲜鸡蛋一只,用注射针头在锐端钻开一个直径约为0.5厘米的圆孔,再用注射器（不上针头）分几次吸出蛋白等物,间或装上针头注入清水,清洗干净内容物以防产生气泡,最后注入滴有红墨水的较浓的蔗糖溶液。 将蛋壳钝端朝上,吸出蔗糖溶液约3毫升,揩干净后用一块小胶布封住圆孔,在熔化的石蜡中过一下,既要封严,又不能产生气泡。 用手电筒照蛋,根据蔗糖溶液的颜色区分出钝端气室的位置,然后钻开一个直径约1厘米的圆孔,不要损伤蛋壳内膜。 此渗透装置放入装有清水的烧杯中,就会进行渗透吸水,内壳膜会变凸。其优点是取材方便,制作简单,携带方便,能大大地缩短演示时间。
Permeation and water absorption is a demonstration experiment that is difficult to achieve experimental results in high school biology classes. The main reason is that it is difficult to find a suitable semipermeable membrane material. Fish bladders, porcine bladders, and casings are all too thick, so the water column rises in the funnel tube of the permeation device is not significant; the egg shell membrane is very thin, but it is easy to break, and it is impossible to seal it in the funnel and penetrate the membrane. After many groping, I found a better way to use the egg shell membrane. Take one fresh egg, drill a round hole with a diameter of about 0.5 cm at the sharp end with a syringe needle, and then use a syringe (not on the needle) to aspirate protein, etc. several times, and put the needle on it to inject clean water to clean the contents. In case of bubbles, the solution is finally filled with a thicker solution of sucrose with red ink. Place the blunt end of the eggshell upwards. Aspirate approximately 3 ml of sucrose solution. Close the hole with a small piece of plastic after cleaning it. Pass it through the molten paraffin and seal it. Do not create air bubbles. Use a flashlight to light up the egg, distinguish the position of the blunt end air chamber according to the color of the sucrose solution, and then drill a circular hole about 1 cm in diameter without damaging the inner shell of the eggshell. When this permeation device is placed in a beaker with clean water, permeation and water absorption will occur, and the inner shell membrane will become convex. Its advantages are easy to draw, simple to make, easy to carry, and can greatly reduce the presentation time.