Sparking Grape in Microwave Explained?

[Elite Engineer]

So, if you split a grape and leave just enough where the skin is attached, and place it in the microwave it sparks, its on Youtube if you haven't seen it. Lots of people say this is plasma, which i think is actually incorrect. Does the grape spark because of the specific conditions with the ski still attached, causing an arc. Is the arc generated via the water and sugars being heated and essentially "arcing" over the grape? I think it's just these specific conditions like make this happen..much like when you crush peppermints in the dark, you see a glimpse of light due to the material on the peppermints...

 

-or I could be wrong too..

 

~EE

[swansont]

Crushing peppermints is triboluminescence or possibly fractoluminescence, which is not what's happening with the grape.

 

https://en.wikipedia.org/wiki/Triboluminescence

[StringJunky]

Any conductive material, including slivers of connecting grapeskin, it seems, with sharp edges has the potential to arc. To arc you need sharp edges and conductive material. Take away one and it won't arc... being made of metal with no sharp edges is not enough. I use metal racks in my microwave, that it came with routinely. If you check the microwaveable racks you will see that the sharpish wire ends protrude beyond any arcable distance to any neighbouring surface. Presumably, that distance exceeds the voltage the microwave is capable of achieving with this design. It's important to prevent spilt food accumulating on it, otherwise it will arc when it turns to carbon and don't let the rack touch the microwave interior wall because it's metal in a dual purpose MW, like mine is.

 

NOTE: Only use racks or other metal objects designed for microwaves otherwise you can damage the magnetron.if there is alot of arcing.

 

 

 

 

[Sensei]

Actually it looks kinda like sodium-potassium discharge tube by color..

One could use prism to split light by their wavelengths, and analyze their spectral lines..

 

According to

https://en.wikipedia.org/wiki/Grape

have plentiful of:

Potassium 191 mg

Magnesium 7 mg

Calcium 10 mg

Sodium 2 mg

(in 100 g of product).

 

What I would try is take some potassium/sodium/calcium/magnesium salts, to two (small) containers with water, solutions, and connect them by little strip of paper to make bridge between them.

And put to microwave oven, and see what happens.

[Elite Engineer]

I've heard this also produces ozone..but I dont really see how or why

[Sensei]

I've heard this also produces ozone..but I dont really see how or why

 

Microwave oven is filled with air, and air is Nitrogen 78% and 21% Oxygen.. ~1% other gases.

While ionization of air, obviously there are produced NO, NO₂, N₂O, O₃.

[Elite Engineer]

 

Microwave oven is filled with air, and air is Nitrogen 78% and 21% Oxygen.. ~1% other gases.

While ionization of air, obviously there are produced NO, NO₂, N₂O, O₃.

So ozone is produced? How stable is the ozone molecule though?