yeah its cool to submerge the stem up to an inch and even more
think of it like when you put roses or any type of flowers in a vase
if you keep the water clean long enuff the flower will root - i have roses do this all the time, no rooting gel no nothing, and for some reason only the bottom most tip of the stem roots no matter how much stem is under water- ive also have had this happen with weed clones - try one just put it in a cup of plain water and when the water looks cloudy change it