The mystery of the glorious fireball emitted by microwaved grapes (featured in my novel Little Brother) has been resolved, thanks to a paper in the Proceedings of the National Academy of Sciences in which Trent University researchers Hamza Khattak and Aaron Slepkov explain how they destroyed a dozen microwaves before figuring out that the grapes were just the right size and had enough humidity to set up standing waves that amplify the microwaves -- and anything roughly grape-sized will do the same.
The paper is offline at both PNAS and Sci-Hub, which is weird, but there's good coverage of it at Ars and Wired.
"Previous explanations leaned on the idea that the grape was acting as an antenna and that an electrical current was being generated across the 'skin bridge' holding the two halves to a grape together," said co-author Pablo Bianucci of Concordia University in Montreal, who did the computer simulations for the study. It's that current, conventional wisdom goes, that generates the plasma.
These new experiments show that's not quite right. The skin bridge isn't necessary for the effect to occur.
Rather, "Our interpretation is that the plasma is generated by an electromagnetic 'hot spot' that is a purely (microwave) bulk effect," said Bianucci. "The grapes have the right refractive index and size to 'trap' microwaves, and putting two of them close together leads to the generation of this hot spot between them."
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I’ve had quite a few fun afternoons playing with dry ice from making spooky fog in the kitchen to exploding plastic bottles in the yard. But I’ve never had the opportunity to pour hot lava over dry ice. In this video, the lava is 1400 °C and the dry ice is -78C°. So cool! And […]
A Boston University team have developed an acoustic, 3D-printed metamaterial whose topology is such that it reflects 94% of human-audible sound; the researchers' demonstration involves inserting a ring of this stuff in a PVC pipe and blasting a speaker down one end: light and air emerges from the other end, but sound does not.
Are you super organized? You’re going to love the Genius Pack G4 and its seemingly limitless, well-placed compartments. Not that organized? You’re still going to love this piece of luggage because it’s so well thought out that it practically does the packing for you. We’ve all tried to stuff a piece of carry-on so full […]
Despite government legislation and improving caller ID technology, robocalls and scam artists are rampant on the phone lines – up to 35 billion a year in the US alone. They can be annoying at best and a financial threat at worst, but there’s a way to take security into your own hands. One good example […]
If you’re a Mac user, you thrive on simplicity. Everything in its place and a place for everything. Unsurprisingly, there’s a ton of great organizational apps out there for Mac, and now someone’s had the great idea to bundle them all together. Whether you’re running a demanding business or just getting through the day to […]