*Flashback Friday*

*This post originally appeared on The PediaBlog on March 4, 2020.


A Viral Experiment



Teacher and behavioral specialist Jaralee Metcalf had a great idea to teach her students the importance of washing one’s hands in order to kill germs. Armed with a simple loaf of bread, some plastic bags, and a classroom of youthful volunteers, Metcalf got to work on her experiment:

To explain how bacteria spread and why it’s important to wash your hands well and often, Jaralee came up with a simple classroom activity with her students: she asked several kids with various levels of hand cleanliness to touch 5 pieces of white bread that were taken from the same loaf, at the same time. Then, they put the bread in individual plastic bags to observe what would happen over the course of one month.


The methods used for this elementary school experiment were not sophisticated:

The first piece was rubbed on all of the classroom laptops. The second one was a control piece — it wasn’t touched, it was placed immediately in the plastic bag and labeled “Fresh & untouched.” The third piece of bread was touched by the whole class using unwashed hands. For piece #4 the whole class washed their hands with warm water & soap and, again, touched the slice. And for bread piece #5, they cleaned their hands with hand sanitizer and then touched it.


One month later, the results of the project were evident when the students taped the plastic bags to the wall. As seen in the photo above, the lessons learned were clear — and maybe a little gross, too: Good, proper hand-washing with plain old soap and water is extremely effective in preventing the spread of germs from hand contact. And nothing, not even anti-bacterial hand sanitizer, replaces it.

Soon after the experiment was completed, the story and the photographs went viral on social media. With everyone talking about influenza outbreaks which sicken millions and kill tens of thousands of Americans every year, and coronavirus (COVID-19), which has already infected hundreds in this country, this little reminder on the importance of simple hand-washing from Jaralee Metcalf’s elementary school students is a service to everyone who wants to stay healthy.