When u break a window with a spark plug, how come you can't hear it?

Answer 1

put lots of duct tape on the window then break the window

Answer 2

Do you mean when it is inside or outside of the car ya use to smash through the window? (makes a big difference..) hey, when ya catapault that lil sucker w/enough velocity the right way?.. well, it's pure magic. Just lob away.

Answer 3

Because when you throw it down the street, you have enough time to run into the house and shut the door, thus eliminating the sound from outside.