How Microwaving Grapes Makes Plasma

Go ahead...do it at home.

Butterfly some grapes and throw them in the microwave.

It's fun. I've done it.

Here's a bit of a how-to...

I always assumed that the water just vaporized which then superheated as the microwaves went through the cloud. That doesn't explain, though, why grapes are so good at doing this.

Apparently it can be done without grapes. They tested using sodium polyacrylate (water gel) beads, and it worked, too.

Turns out there's a lot more to the phenomenon than just superheating the vapor. Apparently the microwaves change wavelength as they pass through the grape/water gel to just the right wavelength to almost exactly match the grape's length.

Fascinating stuff