Teacher Donna Gill Allen has an ingenious teaching hack that is going viral.
The aim? To teach kids the importance of washing their hands, wrote news.com.au.
"This is the grossest yet coolest experiment," she wrote on a Facebook post.
Ms Allen took three pieces of bread. The first piece she simply put into a ziplock bag. For the second she made a point of washing her hands before handling it into the ziplock bag. The third piece of bread was passed around her entire class before being put into the ziplock bag.