Scientists finally figured out why grapes spark in the microwave

Cut a grape part of the way through, leaving two halves that are still connected by a small piece of skin. When placed in the microwave, the radiation causes the grape to increasingly spark from the middle.

- JACQUELINE DETWILER

WHO KNOWS the reasons a scientist may have for choosing the question that will shape his or her life’s work. Maybe, when pondering life’s great mysteries, they prefer the guidance of physics to that of religion. Maybe they have always dreamed of circling the Earth in the International Space Station, watching the Sun rise every 90 minutes over the soapy blue of their home planet. Maybe they accidentally put a fork in a microwave one time. Or maybe it was the microwave thing, but with a grape.

The scientist in question, Aaron Slepkov, discovered the old grape-in-the-microwave trick when he was young. It’s the one where a sliced grape erupts into a fireball of plasma – an ionised gas that is considered the fourth state of matter and is present in large quantities in, among other places, the Sun.

Twenty years later, Slepkov, now a physics professor at Trent University, took on his own experiment to explain how the phenomenon worked. His findings were published in the journal Proceedings of the National Academy of Sciences of the United States of America.