Apr 25, 2020
RAY: This puzzler was submitted by Chuck Leyderer, who writes:
Sargent O'Malley and his rookie assistant Ned are just pulling out of the local donut shop. They get a call on the radio that the town north of them has had a bank robbery. The suspects are proceeding south, and it's a high-speed chase.
The chase has been going on for 40 minutes, and the radio says O'Malley and Ned should be on the lookout for a yellow Mustang with two men in the front seat and a woman in the back.
Just at that moment, they happen to see a yellow Mustang with two guys in the front and a woman in the back. Sargent O'Malley says, "That's the car, Ned! Flip on the siren, and let's get 'em!"
Ned, who's been studying the back of the car, says, "I don't think so, Sarge. It's not them."
What did Ned see?
RAY: What Ned did see coming out of the back of the car was water dripping out of the tailpipe. And if there had been a high-speed chase for 40 minutes --
That engine would be boiling hot . . .
And so would the exhaust system, and that heat would have vaporized all the water that was in that exhaust system. As you know, water is one of the products of combustion, but when the exhaust system gets up to temperature, that water gets converted into steam and it's invisible. So they couldn't have been in a high-speed chase for 40 minutes.