Why Sparks Fly When You Microwave Grapes | Science

YouTubers has become crazy about grapes. In a multitude of Internet videos, kitchen scientists cut a grape almost in half – leaving only a strip of skin connecting the two sides – and stuck it in the microwave. In a few seconds, sparks burst. Now, physicists think they know why this is happening.

The common explanation is that heavy water grapes trap the wavelengths of energy emitted by microwave ovens because the waves are about the same size as the diameter of the grapes. This energy starts to charge electrolytes inside the fruit, which then go from one half of the grapes to the other, using the skin strip as an electrical wire and gaining the same. 39 energy as you go. The stream burns rapidly through the skin, pushing the charged electrolytes to attempt to move from one half of the grape to another, supercharging the surrounding air into an outbreak of bright plasma – the same state of matter emitting the light responsible for the sun's rays. and fluorescent lighting.

To test this hypothesis, the researchers put the grapes in microwaves and watched what was happening with thermal cameras. From the beginning, scientists discovered that a pair of grapes could also produce plasma, provided they were kept within 3 millimeters of each other. The researchers say that if the grapes can produce plasma without the film, the energy that produces the plasma must be formed differently.

The thermal imaging cameras revealed a hot spot between grapes from an accumulation of electromagnetic energy, and not inside the grapes, as predicted by the Internet explanation. This has led physicists to a new explanation: when two grapes are close to each other in a microwave oven, the waves they absorb jostle in the small space that makes them separates, creating an electromagnetic field more and more powerful. This continues until the electromagnetic field becomes so powerful that it overloads nearby electrolytes that spring up in a brief blast of hot plasma, researchers report today. Proceedings of the National Academy of Sciences.

In addition to the damage done by microwave ovens, the authors claim that their discoveries could, with the right materials, one day be extended to trap and focus the visible wavelengths of light for use in microscopy at the nanoscale.