人民教育出版社编写的中师生物教材中,有关光合作用放出氧气的实验是用一大漏斗罩住金鱼藻的方法进行的。在实际操作时,往往有两个困难。其一是我们常常找不到适宜的大漏斗,用的漏斗过小,罩住的金鱼藻少,放出的氧气不多,效果不明显;其二是漏斗下金鱼藻又不能装得太多,否则绿叶挤在一起,中间的绿叶得不到阳光,效果也不会好。鉴于上述原因,我们将此实验作了改进,方法如下: In the Biology Textbook edited by the People’s Education Press, experiments concerning oxygen release from photosynthesis are carried out using a large funnel covering Ceratophyllum. In practice, there are often two difficulties. The first is that we often cannot find suitable large funnels. The funnels used are too small to contain less goldfish and emit little oxygen. The effect is not obvious; the second is that the goldfish algae under the funnel cannot hold too much. Otherwise, the green leaves are crowded together, and the green leaves in the middle get no sunlight, and the effect will not be good. In view of the above reasons, we have improved this experiment as follows: