Experiment MoE10
Synthesis of water: Oxyhydrogen gas bangs
and disappears, negative pressure

* Drop the vial with oxyhydrogen gas produced
   in the previous experiment bottom-up
   into a container filled with red water.
* Remove the stopper with the needles and replace it
   by two isolated copper wires with exposed ends.
* The two ends of the wire projecting from the vial
   are connected to a spark giver.
* By pressing its button an electric spark is produced inside the vial.
Observations: Oxyhydrogen gas explodes, the gas disappears, the vial  is filled by red water.
Explanation:
4 ml of oxyhydrogen gas are transformed into a negligeable quantity of liquid water.
The resulting negative pressure causes the level of red water to rise into the vial.