Bacteria are small but useful, and some will bring trouble to users and make them sick. But some bacteria are used by clever scientists to become useful drugs, food and daily necessities. There are also many useful bacteria in human body. The teacher guides the children to observe the pictures and know what useful bacteria and harmful bacteria look like.
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Precautions:
Washing hands frequently and paying attention to hand hygiene are important means to prevent many infectious diseases. Hand washing is decontamination, allowing harmful microorganisms to be removed from hands, not sterilization. However, washing hands with clean water is far from enough to wash off bacteria. Use soap or hand sanitizer, rub it repeatedly with a small amount of water, and then rinse it under running water.
If you don't wash your hands, you will generally carry 20-30 kinds of germs, which can lead to intestinal diseases, eye diseases, typhoid fever and other diseases. The six-step washing method recommended by WHO can reduce the number of bacteria by 265,438+0%. Many common infectious diseases, such as infectious diarrhea, acute respiratory infectious diseases, intestinal parasitic diseases, skin infections, trachoma and other diseases can be transmitted by hand. Mastering correct hand washing methods and developing good hand washing habits are effective means to prevent the spread of diseases by hand.
Baidu encyclopedia-bacteria
Baidu Encyclopedia-Category (Part II): Health