Magic Car

Last night on the way home, an interesting conversation with my inquisitive daughter took place:

Alanna: Mommy, are we in the Mazda?
Mommy: Yes
A: Does the Versa start the same way the Mazda does?
M: Yes.
A: But you don't have to put the key in the Versa.
M: Oh. No, you're right. The Versa doesn't need the key in the ignition to start, but you do have to have the key with you in order for it to start.
A: (Pause) How does it KNOW you have the key? (Serious tone) Can it see into your pocket?

Truth be told, I don't really know how the car recognizes that the key is in proximity. I resisted my urge to reply that it was simply "magic" and told her that it has something in it that recognizes the key is close. It is a good question though. I guess like many things that are way past my understanding technologically speaking, I just accept that they work without questioning how. I love that she questions the how.

Thank goodness for the power of google:
"Each key contains a chip with an ID code that the car must recognize. In addition, there is a random code that each key receives when the engine is shut off. The vehicle will read and match both codes. If the car cannot match the ID code to the last random code sent to the key in question, it won't start."

Source: http://www.edmunds.com/ownership/audio/articles/106651/article.html

See, I'm getting smarter too in this process!