123456W
ho knows the rea-
sons a scientist
may have for choos-
ing the question
that will shape his
life’s work. Maybe,
when pondering
life’s great mysteries, he prefers
the guidance of physics to that
of religion. Maybe he has always
dreamed of circling the Earth in
the International Space Station,
watching the sun rise every 90
minutes over the soapy blue of his
home planet. Maybe he acciden-
tally put a fork in a microwave one
time. Or maybe it was the micro-
wave thing, but with a grape.
The scientist in question,
Aaron Slepkov, discovered the
old grape-in-the-microwave trick
when he was young, in which a
sliced grape erupts into a fireball
of plasma—an ionized 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 Acad-
emy of Sciences of the United
States of America.
“In 1995, [Slepkov] had found
the first website describing mak-
ing plasma in a microwave, and he
got really fascinated with it and
kept it in the back of his mind,”
study coauthor Pablo Bianucci,
Ph.D., a physics professor at Con-
cordia University, says.
From a thorough inspection of
the internet’s best “microwaved
grape fireball” videos, it seems
to be necessary to cut the grape
in half before microwaving, leav-
ing a small, ion-rich skin bridge
between the two hemispheres.Scientists Finally
Figured Out Why
Grapes Spark in
the Microwave
Cut a grape
part of the way
through, leaving
two halves that
are still con-
nected by a small
piece of skin.
When placed in
the microwave,
the radiation
causes the grape
to increasingly
spark from the
middle.COURTESYPROCEEDINGSOFTHE^ NATIONALACADEMY^ OF^ SCIENCESUSA:"LINKING^ PLASMA^ FORMATION^ IN^ GRAPES^ TO^ MICROWAVE^ RESONANCES^ OF^ AQUEOUSDIMERS"^ HAMZAK.KHATTAK,^PABLO^ BIANUCCI,AND^ AAROND.SLEPKOV-MOVIE^S^130 December 2019
// B Y J A C Q U E L I N E D E T W I L E R //8