These Guys Start a Fire with Nothing but a Plastic Bag Full of Water

Jessica Miley

Did someone say start fire with a bag of water? What? Yes, you heard correctly, here is a video teaching you how to start a fire with a ziplock bag full of water. The video is brought to you by Veritasium, a channel full of engineering videos and great interviews. Ok, back to the fire.

Channel host, Derek Muller, teams up with another YouTube science guy, Grant Thompson aka the King of Random to show us this really awesome and surprising survival trick.

The idea is that you can create a lens from water and a ziplock bag. But you also need to know some basics about fire starting. The guys begin by scrounging for some tinder which they find by breaking bark of a dead looking tree and grinding it with a stone to a super fine powder.

They place this on another flat piece of bark and get to work making their lens. It is ridiculously easy.  They get a standard sandwich bag with a ziplock, fill it half full of water, then carefully ‘scrunch’ the top so a sphere is formed in one corner. They seem to be squeezing pretty hard to get the round shape they need. Once they are happy they simply hold the bag full of water above the tinder and the sun does its work.  

The focal length of the lens, or where all the light converges causes enough heat on the tinder for it to start smoking.  You really need to watch the video to believe just how effective it is. From there it's just a matter of coaxing the hot tinder into flames by adding some more dry grass and a little oxygen! Voila! Never be without fire again (as long as you have a plastic bag, water and a very sunny day!)