with distilled water to a source of direct current,

we can observe a slow evolution of gases.

After some time, we notice that the volume of the gas

released at the cathode is double that of the gas

formed at the anode.

To identify the gassiest products of the reaction,

we collect each gas in and check its behavior

in the presence of a glowing splint.

The characteristic cracking sound proves that

the gas released at the cathode is hydrogen.

The ignition of the glowing splint is evidence of the gas

collected from the anode is oxygen,

which supports combustion.