The kids took five slices of bread and some ziplock plastic bags. The first slice was placed immediately into a bag and labelled "fresh and untouched".
The untouched slice of bread had barely changed in three weeks. Photo / Facebook
For the next slice, each kid washed their hands with soap and water and then they all touched the slice. Then they cleaned their hands with hand sanitiser and all touched a third slice of bread.
Another slice was passed around with unwashed hands and then the last slice was rubbed over the class laptops.
The slice touched with dirty hands grew blue and yellow mould. Photo / Facebook
Metcalf said while they usually cleaned their laptops with wipes, they didn't clean them before doing this experiment to demonstrate how germs can spread.
The slices of bread were all placed into bags, labelled with Post-it notes and left for around three weeks.
The results are startling. The untouched slice and the one that had been passed around hands washed with soap and water had hardly changed.
Metcalf said hand sanitiser was not an alternative to hand washing. Photo / Facebook
The slice lifted with sanitised hands had a patch of mould on one side, while the one touched with dirty hands had blue and yellow mould across the middle.
But the worst one was the slice that had been wiped on the laptops - almost entirely covered in dark blue mould.
The slice that had been wiped on students' laptops had grown the most mould. Photo / Facebook
Metcalf shared the results on Facebook to tell parents to encourage their kids to wash their hands properly.
"We did a science project in class this last month as flu season was starting. As somebody who is sick and tired of being sick and tired of being sick and tired. Wash your hands!
The experiment showed that soap and water is the way to go when it comes to hand washing. Photo / Facebook
"Remind your kids to wash their hands! And hand sanitiser is not an alternative to washing hands!! At all! This is so DISGUSTING!!!'
The post soon went viral, with 17,000 likes and 63,000 shares.
"I want to show this post to everyone that thinks hand sanitiser is better than soap!!!" wrote one Facebook user.
Another commented: "Yuck! But goes to show you that good olde fashioned soap and water is the way to go!"
