To prove methods which are not easier to be polluted through observing the growth of the colony in culture dish when aseptic container being opened,with the inside of the lid being kept up or down in hand.

• 通过观察培养皿的细菌生长情况,研究在打开无菌容器时,保持在手中的盖子,内面翻转向上或是仍朝向下,哪种操作更不易被污染。