Life-saving advice from Creek Stewart in Wired:
Stewart broke open an iPhone, a Motorola Droid and a Blackberry Curve, and Samsung and LG flip-phones; each has a reflective surface behind its screen. “These metal pieces make incredible signal mirrors that can reflect the Sun’s rays towards a rescue plane,” says Stewart.
The jumble of wires in a mobile phone can be used to short-circuit its battery. “If you touch the battery’s plus and minus end with a wire, the wire turns red hot,” says Stewart. The thinner the wire, the quicker it heats up. It can then be used to ignite flammable materials such as wood or dry leaves.