The mechanics behind it are pretty simple too:
The white-hot liquid glass is hot enough to light the branch on fire.
While the branch is catching on fire, the liquid glass coats it completely, trapping the plant matter away from oxygen, and it can't continue burning without oxygen.
That's how you catch the branch in the state of "plant catching on fire", without advancing to the "plant burnt" state.
The physics and artistry of this are fascinating but I love how they have to cut the molten glass with shears like it’s unruly fondue



















