Ninja rocks are broken shards of spark plugs that are formed by smashing the ceramic portion of the spark plug with a hammer or other large object. Since they can quickly and quietly fracture the glass side windows on most cars, ninja rocks have been used in "smash-and-grab" auto burglaries since at least 1995.
Does this mean if I throw a spark plug to someone's head with the same force it takes to shatter the glass, I would break his skull? Whoa, didn't expect that. They seem to throw the spark plug rather casually in the videos. Edit: what about the impact absorbency (?) of the hair and skin?
Spark plug fragments may not break glass if they are not sharp enough or thrown with too little force. Spark plug porcelain shards are also less effective on windshields because these come with a special laminate feature that reinforces their resistance to impact. In some states, broken shards of spark plugs are considered a weapon.
Um, you probably shouldn't have had glass around the open spark plug hole in the first place. this could make it hard for your spark plug to fit into place, or even send the spark to the cylinder.
Could have been the heat, or a pebble, or a spark plug. A glass expert told me that heat can shatter a window. And my mom's rear window was shattered from a pebble and we didn't even hear anything except the glass crackling, and saw the pebble stuck in the glass.
It's not loud but it's not silent. The glass is saftey glass so it doesn't shatter into big pieces and fall out. It will spiderweb and stay in place till you push it out. Thats why it's so quiet. There is no sound of glass splilling all over. And yes I have done it with the ceramic from spark plug. It works extremely well.
How to shatter a car's tempered-glass window using a busted spark plug ... It shows just what it takes to get through a car window and gives a handy hint on how to breach through tempered glass in ...
Shatter a Car Window with a Sparkplug in an Emergency. ... this video that if you break off a chunk of ceramic from around the sparkplug and use it against the car window safety glass, it'll ...