This app is useful for all ages. While it is unlikely that you will have a charger when you suddenly find yourself needing the data in this app, having it on your iDevice will allow you to take the time to study and practice the techniques. With it, you can learn basics of survival medicine, how to make a shelter, how to procure water, and other vital tools for camping, or the "just in case" situation.
Survival Guide is completely based on the U.S. Military Survival Manual FM 21-76. Pretty cool idea for an app actually. It has very high ratings in the App Store and worth checking out!
Compatible with iPhone, iPad, and iPod touch.