Starting African Violets using hydroponics

My class is using hydroponics to start African Violets for Mother's Day gifts. I researched online and couldn't find much information.

We cut the stem at a 45 degree angle and inserted it into a small jar w/ the stem placed through a hole in a paper towel to hold the leaf. The stem is in water.

Will this work? If so, how long does it take to root. If not, any suggestions?