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Grape Balls of Fire

Trent University professor Dr. Aaron Slepkov worked with seven undergraduate students to answer the question of why microwaved grapes become a fireball light show. The students played a key role in the professor’s recently published Grape Balls of Fire research, which is getting serious attention across the globe.

“I have access to excellent undergrads—smart, well-trained and curious students—and that’s why this got done at Trent and nowhere else,” says Dr. Aaron Slepkov, a faculty member in the Physics department at Trent and This link will take you to another Web site Canada Research Chair in the Physics of Biomaterials.

Working together, the team has answered the question of why microwaved grapes become a fireball, producing light and sparks. The research published in This link will take you to another Web site Proceedings of the National Academy of Sciences (English only), shows that the light show is actually plasma made up of ions and free electrons that aren’t tied to atoms or molecules.

The paper, co-authored by Dr. Pablo Bianucci, a physics professor at Concordia University, shows that the same effect happens in any two objects made mostly of water and that have the right size such as quail eggs, hydrogel beads, blueberries, olives and gooseberries.

Professor Slepkov first heard about this phenomenon when he was an undergraduate student himself in the 1990s and, over the years, he would often spark grapes in microwaves as a “party trick.” After becoming faculty at Trent, he started to research the topic in 2013 with Aaron Curtis, an undergraduate student who was coming home to Peterborough for the summer and wanted to volunteer in his lab.

After Mr. Curtis made great headway that summer, Prof. Slepkov knew he was on to something and the project blossomed over the years to include four Trent undergraduate students including some recipients of Undergraduate Student Research Awards.

Prof. Slepkov says all of the undergrads were bright, curious and hardworking students who have all gone on to graduate studies. “It was the students who were the real resource in this case,” he says.

This article was adapted with permission from This link will take you to another Web site Trent University (English only).