If you've been following our site for a while now, you know that we're typically not big fans of so-called “life hack” videos. Most of the time, they're demonstrations of needlessly complicated solutions to problems almost no one actually has — like cooking an egg using a soda can, butane lighter, and rubber bands (as seen here). We appreciate creative problem-solving, but it's not necessary to re-invent the wheel with items from your junk drawer when a dozen easier and better solutions already exist.
That said, every once in a while we see one of these videos that demonstrates a technique that might actually come in handy someday. Such is the case with the following video from the YouTube channel DaveHax. This minute-and-a-half clip shows how to cut a strand of string, rope, or paracord by doubling it onto itself and forming a friction saw.
The rope is laid flat on the ground beneath your feet with a slight arch in the middle. One end is passed over the top, looped under the arch, and quickly sawed back and forth to sever the rope. You may recognize this as the same technique used to cut through zip tie handcuffs with a shoelace or hidden kevlar cord, because the principle is the same. You're just moving your hands instead of your feet.
In most cases, it goes without saying that you should already have a knife on hand. But in case your cutting tool is lost, damaged, or not readily available, this technique could be helpful. Better yet, it doesn't require toothpicks, twine, a hot glue gun, or a wad of chewing gum like so many other “life hack” techniques. Note that with paracord and other multi-strand nylon ropes, you'll still want a lighter to melt the ends and prevent fraying, if possible.