Learn how to Start a Fire With a Plastic Bag and Some Water

[C C]

http://nerdist.com/learn-how-to-start-a-...ome-water/

EXCEREPT: [...] In the video, Thompson explains the process you’ll need to follow in order to show off on your next camping trip and Muller explains a bit of the science. By pinching off the water-filled bag and twisting it until it bulges a bit from the pressure you’re essentially making a bi-convex spherical lens. In other words, a magnifying glass. Getting some sun on it and aiming its focal length at some properly prepared tinder will have it smoking in no time....

[Magical Realist]

I still like the old wooden stick method---preferably when they're tipped with phosphorus and potassium chlorate.