Dear Car Talk:

I was wondering if there is a way for gas stations to add water to their tanks to make the gas stretch farther. I heard differing points of view about this when I posted this question on a popular social-media Q-and-A forum. Some say gas and water don't mix, so it would be impossible; others say it would destroy the machinery involved, as it wasn't made to handle water; others say it's very possible. What do you say?

-- Julie

It's possible. And it's also impossible, Julie. More to the point, it's possible for gasoline and water to mix temporarily.

If you shake up a container of water and gasoline, the water will be briefly suspended in the gasoline, but will quickly separate back out, with the water going to the bottom and the gasoline staying on top.

That's why this trick is popular right now only with gas stations in Oklahoma, where they have about 5,000 earthquakes a month, thanks to fracking. That keeps those underground storage tanks shaken up nicely.

So the overall answer is no, it does not make sense for gas stations to do this, Julie. The water would sink to the bottom of their storage tanks, taking up space, and reducing the amount of gasoline they could store and sell.

And since the water would separate out, some customers would get only water, which would leave the gas station with a lot of 'splainin' to do.