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科学实验是科学课的重点,当教学内容涉及实验时,科学教师总是在办公室先做一遍,以防课堂演示时出现错误。其实我觉得不一定上课时做得实验尽善尽美就是好的,学生就能把该掌握的要点记住,其实不然。这些日子我刚好在教学“氧气的制取、性质、用途”等内容。那天,我事先在办公室制取氧气,我从实验室拿了些仪器、药品。我准备先用二氧化锰和双氧水制取氧气,看到实验室储存的双氧水的浓度是30%,我就加一倍的水进行稀释。当我把稀释的双氧水倒入盛有二氧化锰的烧瓶时,液体从瓶口喷了出来,喷了一桌子
Science experiments are the focus of science lessons. When the teaching involves experiments, science teachers always do the first thing in the office to prevent mistakes in classroom presentation. In fact, I do not think it is a good idea to have an experiment done in class. The students can remember the points they master, which is not the case. These days I am just teaching “Preparation of Oxygen, Nature, Use ” and so on. That day, I prepared oxygen in the office in advance, and I took some instruments and medicines from the laboratory. I am prepared to use oxygen dioxide from manganese dioxide and hydrogen peroxide. When I see that the concentration of hydrogen peroxide in the laboratory is 30%, I dilute it twice with water. When I poured the diluted hydrogen peroxide into a flask filled with manganese dioxide, the liquid was sprayed from the mouth of the bottle and sprayed on a table