Everyone knows what a gallon of gasoline is, or what they paid the last time they put fuel in their car.
But trying asking your friends, relatives, and neighbors how much they paid per kilowatt-hour in their last electric bill. Or even what a kilowatt-hour is.
We guarantee you that 19 out of 20 of them won't have a clue.
It's relevant to green cars because charging the battery of an electric vehicle requires the purchase of kilowatt-hours of electricity.
We might suggest that electric-car owners are much more likely to know what their last kwh cost them.
But not only is the term "kilowatt-hour" unknown—or at least deeply mysterious—to a whole lot of people, so are the most basic principles about electricity and electric utilities.
Frame from man-on-the-street interviews on electricity, utilities by E-Source LLC, 2011 [YouTube]
A 2011 video of "man on the street" interviews by E-Source LLC underscores that point with some gentle humor.
Interviewer Bill LeBlanc takes to the boardwalk in what appears to be Redondo Beach, California, to ask passers-by a few questions about their utility and its services.
Those include what electricity actually is, how it works, and what they think of their electric service.
Over the 9-minute video, the interviewees also weigh in on what kind of animal their electric utility would be.
Not to mention how an Easy-Bake Oven works. And its "boy" equivalent.
You'll even find out about "vegetarian electricity."
2011 Nissan Leaf and 2011 Chevy Volt, with charging station visible; photo by George Parrott
But what we'd have liked to see would have been a question about the mysterious kilowatt-hour, how much work it can deliver, and what it might cost.
We'd bet that not a single interviewee could name the cost of the kilowatt-hours they consume, or how many.
If you're skeptical that the public may really be that unaware, try asking the questions in the video to family, friends, and colleagues.
We strongly suspect that virtually no one will be able to say how electricity works, how much they use, or what they pay for it.
The Energy Information Administration says the average U.S. household uses a bit more than 30 kwh a day, by the way, costing an average of 12 cents per kwh.
We've been asking these two questions for a couple of years now, and the results are generally amusing—if indicative of how far we still have to go in educating the public about how you recharge an electric car.
2017 Chevrolet Bolt EV electric car at EVgo fast-charging station, Newport Centre, Jersey City, NJ
This is one, in other words, that you can safely try at home.
The results may surprise you—especially if you already own an electric car.