Why does the porcelain/ceramic in a spark plug break tempered glass?

Question

When you throw a small piece of the white ceramic/ porcelain of a spark plug at tempered glass it shatters it easily, why?

Answer 1

"throw a small piece" seems unlikely unless small is most of the porcelain and it is thrown hard and hits on a broken edge. Tempered glass will break if it is even slightly chipped or scratched which is what the hard porcelain might do, although normally I would expect it to bounce right off. The escape tools sold to carry in cars are basically a very hard point to chip the tempered glass in a side window which then disintegrates into thousands of small cubes.

Holding a small piece and using a corner of the porcelain to scratch would probably work.

Answer 2

Mike1942f you dont understand. you can throw a small piece of porcelain at a perfectly good car window, and it will literally shatter. it has something to do with the crystallinity of porcelain. porcelain is made through a process of heating, cooling and reheating ordinary glass, which produces properties of both glass and ceramic materials. it is extremely tough and my suspicion is that the harmonic wavelength of the porcelain (Hrz) vibrates at the right frequency to shatter the glass. anyone else know anything?

Answer 3

A blueberry size piece of spark plug insulator will shatter the whole thing. Dont get me wrong, you have to Throw it. Not a toss. Bricks and hammers always failed us. Me and my sister used to sneak into the junk yard and break stuff