[myself248]

One of the interview questions where I work (we do automotive electronics) is "Explain how GPS works." It's directly relevant to the job, but it's also a neat opportunity to see how someone sizes up their audience, manages time and assumptions, etc.

All those things are neat, but mostly what I've learned is that quite a lot of people, otherwise apparently reasonably smart and competent and toting a whole stack of prestigious degrees, have ghastly flaws in their mental model of what GPS is.

[mikewarot]

If you think that's bad.... try asking someone where they think electricity comes from.

[jeffbee]

I personally blame the rabid Libertarians that the other guy mentioned. Tons of people think that what GPS does is sends your location to the Air Force, which is a bit backwards (and doesn't pencil out in terms of either energy balance for the mobile station or channel capacity for the satellites). They think this because that's how people casually write about it (the FBI was tracking me over GPS, or whatever).