Size anologies of Bacteria and Viruses

This short video clip presents various analogies so we can better visualize the size of viruses and bacteria. It was said that viruses and bacteria are submicroscopic and that therefore we cannot see them with the naked eye. There is a big difference in size between them. In order to get a sense of their scale, we can take the human body to represent a single cell. Then the large viruses, like those of the smallpox, would be the size of a battery, and the small viruses, such as polio, the size of a tiny tablet, while a million bacteria would be the size of one big room. When measured by a ruler that is divided in inches, centimeters and millimeters, the bacteria are the size of 0.001 mm (or one thousandth of a millimeter). We can never see a single organism (bacterium) but only the whole colony. Although they are very tiny, they play a significant role in our lives. In our microbiology class, we learned that microbes or microorganisms are organisms that are generally too small to be detected with a naked eye and therefore can only be seen with a microscope. Plants, animals and humans all need them for survival and as such they are an integral part of our lives. Moreover, billions of them live in our bodies and we need them in order to stay healthy. Because they can also cause diseases, it is essential for us to understand how microbes work, how they can affect our health, and how we can use them for our benefit. Since we depend on them, we need to understand the biological processes of microbes that are common to all organisms and our ecosystem. We also learned that they can be beneficial or pathogenic; luckily for us, there are more beneficial microbes than pathogenic (less than 1%). It was also gratifying to learn that microorganisms are used in making wine, yogurt, alcohol, cheese, and sour kraut. On the other hand, medical science has developed antibiotics, vaccines and antiseptic methods to fight pathogenic microbes. Thus, handwashing was always considered important (to reduce infections), but now that we know more about microbes, it is crucial.

http://www.hhmi.org/biointeractive/media/size_analogies-lg.mov