fire

And dangerous

It is not at all difficult! And, don't you know,Angel? Boys like being dangerous! It's how things get invented.

I don't think you can do that. But i don't know much about science or physics.

Okay,Moonwind, and others. A simple science lesson. If you are making jam (jelly) and put the boiling jam into a cold jar, the jar will shatter.Because the inside of the jar is hotter than the outside,causing stress on the glass.But even your old grandma would know that if you heat the glass first it would not break!
It is the same with putting fire into a glass jar. If the inside is hot, and the outside cold, the jar will break; usually at the thickest part.But, heat the jar, and you can put a small fire in it.
However, if the outside of the jar cools quicker than the inside; the jar will no doubt break.