What are bacteria?
Bacteria are microbes - living things so small that you can only see them using a powerful microscope. They are found everywhere. Most bacteria will not harm us. Some are useful to us such as those we use in yoghurt and cheese- making. Some bacteria make vitamins to help us digest food. Other bacteria cause food to rot.
Only a very small number of the millions of different bacteria around us are actually harmful.
How bacteria multiply:
Bacteria multiply by splitting into two. This is called binary fission.
Give bacteria food, warmth, moisture and time, and each one will soon become millions.
Some bacteria only take between 10 and 20 minutes to divide.
It may take only 9 hours for one bacterium to become 100 million. You still may not see them, as all 100 million would only be the size of a pinhead!
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