IDAHO FALLS, Idaho (CBS Local) — A classroom science experiment in Idaho goes viral in more ways than one.

With flu season in full swing, Dayna Robertson’s class at Discovery Elementary in Idaho Falls decided to see just how important it is to wash our hands.

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The experiment separated five pieces of plain white bread into different ziplock bags. One was touched with dirty hands, another with hands washed with soap and water, one touched with hands that used hand sanitizer, another slice was wiped on laptops and one was kept fresh and untouched.

The process took about four weeks because of preservatives in the white bread.

Jaralee Metcalf, a behavior specialist at Bonneville School District 93, shared the results on her Facebook page and the post went viral with more than 600 shares.

“This is so DISGUSTING!!!” she wrote.

The untouched bread remained clean and the bread that was wiped down with soap and warm water didn’t show widespread mold.

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But the piece touched by unwashed hands was covered in greenish-gray mold and the one wiped on Chromebook computers was almost completely black and coming apart.

And perhaps the biggest surprise was the bread touched by kids who used hand sanitizer showed a rainbow-colored mold.

“You know everybody kind of relies on those hand sanitizers to and to see results that were this drastic kind of made everybody realize that maybe we’re a little bit dirtier than we thought,” Robertson told KIFI.

Although the bread will ultimately get thrown away, the impact it made will remain.

“We’ve been wiping things down and washing our hands more frequently,” Robertson said.

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“Always wash your hands,” a student named Lincoln said.