Assuming a scientist has two canisters: One with a liter of pure gas of hydrogen (single atoms gas), and one with half a liter of pure gas of oxygen (single atoms gas).
The scientist desires to conjunct the two single atom gasses inside some instrument somehow, to create water.
I understand that the process of doing so is some kind of explosion.
What are the names of that reaction and of the instrument in which it should take place?
I ask this after I saw the film "The Martian", in which the protagonist "Mark Watney" created water from separating hydrogen from hydrazine, then burning it with oxygen in extremely low stream of gasses, creating very small amount of water in each step of a process.
Here is a video in which a youtuber seemingly creates water from burning hyrdogen and oxygen (legal note: I ask any reader not to try this without being certified as a chemist from, a internationally known academic center).
This question is for general knowledge: To know the name of the reaction and the common instrument for it.