Soda versus pop... don't forget Coke

Forget the shocking cold in the winter or the sticky humidity in the summer.
The biggest culture shock when I came to college in IOWA all those years ago was that when people wanted a Pepsi or Coke, they asked for a POP.
Pop? What do you mean? Do you want a SODA?
Thanks to a map produced by the Department of Cartography and Geography at EAST CENTRAL UNIVERSITY (OKLAHOMA), I now understand the basic scenario leading to my initial confusion.
I came from CALIFORNIA, where the word "soda" almost universally means the sweet, carbonated beverage that people in Iowa mostly call "pop."
I have lived in Iowa 15 years and I still call it "soda," but my daughters (confusingly) call it "pop."
Intriguingly, the soda versus pop question becomes moot when you travel south.
Last December, I visited ATLANTA, where the Southerners all call it "COKE."