As more people on the coasts move to the Midlands seeking the friendly safety of unwashed hog farmers here in the Midwest (And bringing the problems they are trying to escape with them, I may add. Heh.) I have begun saying "soda" more often than "pop" so that our newcomers may understand our quaint speech.
When I was growing up a soda was flavored syrup with CO2 in it and a couple of scoops of ice cream added. This dates back to the soda fountains of old.