Bread rubbed on laptops turns black in students' experiment

WABC logo
Thursday, December 19, 2019
Students test for germs using bread
Students test for germs using bread: as seen on Action News Mornings on December 19, 2019.

IDAHO FALLS, Idaho -- With flu season upon us, Ms. Robertson's class at Discovery Elementary in Idaho decided to use bread to see just how important it is to wash our hands.

"Everybody touched it and made sure that we got it nice and dirty," teacher Dayna Robertson told KIDK-TV.

The experiment separated five pieces of bread into different Ziploc bags.

Before each slice was stored, it was either rubbed on classroom laptops, passed around students with dirty hands, given to students who had used hand sanitizer, or handled after the students had washed their hands with soap and water.

The final piece was stored fresh and untouched.

"I didn't think it was going to be as shocking as they were," Robertson said.

After three to four weeks, students started to see their classroom germs come alive before their eyes.

The bread that was rubbed on the classroom laptops had turned completely black.

An even bigger shocker was the mold that formed on the piece of bread that had been passed around after the students used hand sanitizer.

Behavioral specialist Jaralee Metcalf shared the experiments results on her Facebook page, and the post went viral.

"Tagging their friends or other teachers and being like 'have you ever done this,' 'you should do this,' 'this is so cool.' A lot of 'that's really gross' because it is really gross," Metcalf said.

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.