You take a grape, cut it in two parts, which are connected with a piece of skin, put the Whole thing in the microwave, place these on the highest level – and zack: plasma flash. Only a few seconds must be waited until the grapes tremble halves, and finally, glowing balls of light above them, sparks.
you do not need to reproduce this Experiment to see the effect: a number of people have carried out in the network, apparently, is the “grape plasma trick” known to trial already.
wine grapes are just the latest item among the things that were used for experiments already in a microwave. However, the grapes-Plasma employed for the Amateur physicists in the Internet. In forums has been discussed for a Long time, as the lightning is actually produced.
Plasma is also referred to as the fourth state of aggregation. It is formed when supplying gases, with sufficient energy, for example by Heating. Thus, an electrically conductive mixture of positively charged ions is formed, surrounded by free electrons. The mixture begins to glow when the free electrons of the ions are captured and previously captured energy in the Form of light. The question of how the Plasma bolts in the microwave.
the Decisive factor is the contact between the grape halves
A study of Canada’s Trent University, it should solve the puzzle now, Once and for all. A group of canadian researchers Aaron Slepkov found out: The round shape of the grapes and the properties of water are crucial. Their results, the scientists in the journal Proceedings (PNAS) of the US National Academy of Sciences published.
Previous explanations for this phenomenon have always emphasized the role of the skin and open the wet surface, the researchers write. “We note, however, that none of these components for the formation of the plasma is essential.” A closer look at the development of plasma lightning show, that the ignition is below the “skin bridge” would be held between the two grape halves.
First of all, the researchers concluded that whole grapes and balls of the Hydrogel, for the most part consists of water, plasma flashes can occur when they are irradiated with microwaves. It is crucial that there is a contact between the grapes or balls. This contact can also consist of thermal paper, which changes color at a temperature of 85 degrees Celsius dark.
sodium and potassium in the Plasma and in the grape skin
are Important according to the study, so-called Hotspots, which are formed in the middle between the grape. This form on the one hand because of the round shape of the grapes, in which electromagnetic waves in a certain way are scattered. On the other hand, the water inside the grapes is crucial: When researchers in one Test, two touching put at the end of quail eggs in the microwave, was a Hotspot between them, if the egg shells were filled. The shells had been emptied by a small hole, not the Hotspot.
What’s happening now with the Hotspot between the grape halves? The scientists performed a spectral analysis of the plasma flash. They came across sodium and potassium – chemical elements, which are in the grape skin. Because the electric field of the microwave radiation is concentrated in the Hotspot, are ionized, these atoms partially. Then you are no longer electrically neutral. The sodium and potassium ions with the wavelength of the microwaves in resonance and can also ionize the surrounding air, so that a Plasma bolt.