A physicist and a political science major walk into a bar. Let's call them Steve and Joe, respectively. They have a few drinks, play a few rounds of pool, the usual.
At some point, the two get bored and start playing betting games. Steve is really on a roll, having learned a thing or two about unintuitive parlor tricks in his time.
His friend isn't such a poor sport, but Joe's got to get at least one good shot out of it. So he makes a simple bet.
"I can show you how to light water on fire," poses the PoliSci major.
Well, being a physicist, Steve could think of a few loopholes, and qualifies the bet. "What sort of water?"
"Just any old tap water," Joe answers.
"No way," the physicist challenges.
Steve pops a half-smirk, having trapped his friend. "Oh, but you can. Just watch me."
So Joe orders a glass of tap water himself, just to be sure his peer wasn't pulling his leg. "All right; if you're so sure, blow my mind."
"As you wish, Mr. Science Man." Steve puts a lighter to the edge of the glass and — fwoomph — out shoots a bellow of flame. Steve promptly covers the glass with a towel before the fire gets out of hand.
The physicist picks his jaw off the counter and shouts, "How?!"
"Joe, we're in California. Haven't you heard about the fracking frenzy, yet?"
The physicist crosses his arms stubbornly. "I'm not paying."
Steve laughs light-heartedly. "Why not?"
Joe points emphatically with both arms toward the glass.
"It's not even real water!"