Let's say you drop accidentally your iPhone in water (not sea water as salt will be easily spotted), you can always try to send it back to Apple Support for having it repair under warranty. To avoid such behavior, Apple has included a water sensor in the iPhone and in the iPod Touch:



At the bottom of the jack plug you can see a white disc that will irreversibly change color when entering in contact with water. So one would not need to open an iPhone or an iPod Touch to ensure it stopped working due to an unexpected bath.
Hereafter it the same disc in the iPod Touch.



We did not have the opportunity to check if such system was also added to the last iPod nano and iPod Classic.

[translation by Linathael]

very interesting. does it revert to the original color after drying (or after some extended period of time)?

no
read again the news: " irreversibly change color "

ha! thanks! i must not skip words!
if it changes back, how would it help Apple to refuse support, without opening the case?

exactly
it changes color irreversibly, and then Apple Support simply need to look at it before accepting to repair a faulty device.
I wonder how it works in humid environment...

humid climate - maybe total decolorization after time?
but it sure is interesting to have such a feature. maybe in time to come, we have a pod that sings to us, "singing in the rain" ...

I have a new 3G that I was able to find the sensor in the earphone jack....however, much to my chagrine I found out they also stuck a sensor in the other end charging entrance.....It looks like a square white area......they hoodwinked us again.....anyone else see this?