Assertion: spark plug's shell | /r/CapableOf | act as the ground
Facets:
value: for the sparks
type: PURPOSE
Source sentences:
text: The metal case/shell (or the jacket, as many people call it) of the spark plug withstands the torque of tightening the plug, serves to remove heat from the insulator and pass it on to the cylinder head, and acts as the ground for the sparks passing through the central electrode to the side electrode.