You know about the volcano experiment that all 4th graders do (when you're about nine years old). Baking soda and vinegar. We did it in class. The thing explodes.
File that bit of info in the recesses of the mind somewhere.
The next bit to file: My teacher in 5th grade (that's a year later) telling the class that she sips baking soda water whenever she has an upset tummy. You just mix a little baking soda in a glass of water, and down the hatch it goes -- instant relief.
Bit filed somewhere else in the recesses of my mind.
Several years go by. I used to like to sip vinegar. (I wouldn't touch it with a 10-foot pole now, but that's beside the point.) I got an upset stomach. I remembered the 5th grade teacher's handy recommendation to drink some baking soda water. I mix up some baking soda water and drink it down.
BOOM!!! A ball of volcanic gas about the size of a grapefruit happened inside my stomach (I'm surprised it didn't rupture), which then immediately blew out as a gigantic burp.
It was at this point that I remembered the volcano experiment....