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“植物对水分的吸收”是新华师大版八年级上第六章第二节的内容.为了帮助学生理解植物根毛是怎样吸收水分的,教材中安排了“植物细胞的吸水和失水”实验,过程如下:将两块大小和质量都相同的条状萝卜分别放入20%Na Cl水溶液和清水中.一段时间后,比较两个萝卜条的质量和形状,通过质量的变化和形状软硬的变化来帮助学生认识植物细胞的吸水和失水.然而在过去的教学实践中,我发现该实验存在以下不足:
“Plant water absorption” is Xinhua Normal University eighth grade sixth chapter second section content.In order to help students understand how plant root hair absorbs moisture, the textbook arranged “water absorption and loss of plant cells Water ”experiment as follows: Two strips of radish of equal size and mass were placed in 20% aqueous NaCl solution and fresh water, respectively.After a period of time, the quality and shape of the two radish strips were compared, And changes in shape and soft to help students understand the plant cells of water and water loss.In past teaching practice, however, I found that the experiment has the following deficiencies: