Tin cans seem too heavy and cumbersome to bring along while camping or backpacking, but there are so many clever uses for an empty can they make a great addition to your pack. Of course, you'll have to pack a can opener too...
Anyhoo, this fun video by Specific Love Creations shows you how to turn a lid from a metal can into a survival whistle, so you won't lose your friends while you're out getting lost in the woods.
Or just make one at home and drive your pets crazy!
-Via Lifehacker