cr15py
Abbriviations, I'd traverse the web and become a bit more Internet-savvy before you start talking.
Due to the fact that I'm on mobile I'll check if they explode later, but the obvious thing to do is spark the center of the bulb. So you sparked the side of it, correct? That disrupts the balance in the noble and causes it to explode.
QED
EDIT: Ok, it's probably like jma1111 said below and you used a mod. I just tested them and it doesn't matter where you spark them.
Btw I think I fixed your tiny one, I just shrunk the ratios.
LoadSaveBlock(51721);

cr15py
When you used mine where you on a mod?