Here is a concise summary of the text:
**Title:** The Science Behind Microwaving Grapes to Create Plasma
**Summary:**
* A YouTube video from 8 years ago showed creating plasma by microwaving a cut grape, but the explanation was incomplete.
* Recently, three scientists published a study in the Proceedings of the National Academy of Sciences explaining the phenomenon.
* Key findings:
+ Microwaves become trapped inside the grape due to its high refractive index and size (comparable to the microwave wavelength inside the grape).
+ Trapped microwaves create strong electromagnetic fields, especially when two grapes are in close proximity.
+ These fields can ionize air, creating sparks and plasma, primarily composed of potassium and sodium ions.
* Implications:
+ The phenomenon could inspire new lithography techniques for fabricating microchips, enabling the creation of smaller features using focused electromagnetic energy or light.
Here are the key facts extracted from the text, without opinions, with each fact numbered and in short sentences:
**Microwave and Grape Experiment**
1. A grape can create plasma when microwaved after being cut almost completely in half.
2. The experiment was initially conducted without a clear understanding of the underlying physics.
3. Three scientists have since published an explanation in the Proceedings of the National Academy of Sciences.
**Microwave Properties**
4. Typical household microwaves use a frequency of approximately 2.45 gigahertz.
5. The wavelength of microwaves inside a microwave oven is about 12 centimeters.
6. Microwaves travel about 10 times slower through a grape than through air.
**Grape Properties and Interaction with Microwaves**
7. A grape's index of refraction in the microwave regime is almost 10.
8. The wavelength of microwaves inside a grape is about 1.2 centimeters, roughly the size of a grape.
9. Microwaves become trapped inside a grape due to its high refractive index and size.
10. Trapped microwaves form resonant modes (standing waves) inside the grape, with maximum electromagnetic field intensity at the center.
**Effects with Multiple Grapes**
11. Two grapes placed side-by-side can produce the plasma effect as long as they stay in contact.
12. The strongest electromagnetic field occurs at the contact point between two touching grapes.
13. This contact point is where the grapes get hottest and can produce sparks due to air breakdown.
**Composition of Plasma**
14. The plasma created from a grape contains ions of potassium and sodium, as identified by emission lines in the plasma's spectrum.
**Applicability and Size Considerations**
15. The size of the grapes is important for the effect, but not critical due to water's microwave absorption broadening the effective size range.
16. The phenomenon could potentially be used to improve lithography techniques in microchip fabrication by focusing electromagnetic energy to a tiny spot.
**General**
17. Hydrogel water beads can also produce a similar plasma effect when microwaved, demonstrating the effect is not exclusive to grapes.