What is the Importance of Hygiene?

by Leah
(Jamestown, NY)

I obtained Petri dishes from a local high school lab and took samples from various sources to show the importance of cleanliness.

Samples were taken from: unwashed versus washed hands, new vs. old toothbrushes, and we had someone cough directly onto a Petri dish vs. having their mouth covered. The Petri dishes were grown out for 3 days and the number of bacteria colonies were counted.

As hypothesized, using good hygiene (the washed hands, new toothbrushes, and covered mouth samples) produced fewer bacterial colonies. As the actual bacterial samples could not be displayed with the poster board, we took large photographs of the results and placed those in front of the poster board for examination.

This was a fourth grade level project.

Barry's Response - Pretty advanced for fourth grade, Leah. Congratulations.

As you've probably noticed, the use of alcohol-containing hand sanitizers has become quite popular in public areas lately. Alcohol kills enough bacteria (and some viruses) to make their use worthwhile and their effectiveness is enhanced when coupled with proper handwashing. Still, the better solutions (greater than 60% alcohol, isopropanol usually) are quite effective even in situations where washing is not an option.

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