CBS Local — A North Carolina teacher’s stomach-turning experiment has become a social media sensation and a new way to get stubborn kids to wash their hands.

Donna Gill Allen posted her novel approach of showing students how dirty their hands can be to Facebook in August. The teacher taped three bags to the wall, one bag for an untouched piece of bread, one for a piece touched by freshly washed hands, and one for a piece touched by her students’ unwashed hands.

The teacher’s moldy lesson paid off as the bread touched by dirty hands eventually turned into a disgusting, green mess before the others did.

“Watch how the bread changes over time due to germs. It is so cool and a great way to teach the importance of hand washing,” Mrs. Allen wrote in her post. She reportedly shared it with just her fellow teachers but the post quickly spread all over social media with more than 70,000 shares and 14,000 comments.

“Visual learning always helps the point to stay in our brains,” one person wrote about the “germy bread” experiment. Others also added how Allen’s lesson wasn’t just for young children. “We should show this experiment at my job,” the comment read. “Forget kids I know some fully grown adults that could use the lesson!”