You flush the toilet, wash your hands and now, as warm water cascades down your fingertips, you face a critical decision: Should you use some paper towels, the hand dryer, or stick it to the Man and wipe those damps hands on your pants?
You have your nice pants on today, and despite hand dryers being marginally better for the environment, you eventually decide on paper towels, the more hygienic and convenient option. But then you face another tough decision: Should you crumple a few sheets into a super absorbent ball; attempt to make the most of a single sheet by meticulously folding it into a layered sponge; or unravel the entire roll and dance a celebratory ribbon dance around the bathroom?
If you care about the environment and hate to be wasteful — especially considering Americans use paper towels as if trees grew on, well, even more trees — you’re probably looking to get the job done with a single towel (maybe two). But will that be enough to ensure you leave the bathroom with dry hands?
Joe Smith, an advocate for practical paper towel use, once gave a TED Talk in which he proposed a simple method that allegedly requires only one sheet: After washing your hands, vigorously shake them to remove any excess water, then simply fold the paper towel before using it to dry your hands. This technique, he explains, increases the absorbing abilities of the paper towel by means of a scientific phenomenon known as interstitial suspension (more on that in a moment).
Both skeptical and confused after watching this TED Talk, I asked MIT scientist Alex Klotz to enlighten me with some paper towel science. “The physics of hand drying involves water being transferred from the hands to the surfaces of the many fibers that make up a paper towel,” he explains. “Because entropy tends to increase, water is likely to diffuse from a region of high concentration to one of low concentration, but not the other way around. This proceeds until the paper is saturated and can’t absorb any more water, or until there’s no more water to be absorbed. The thicker the towel is, the more water it can absorb. First, the layer touching the hand becomes saturated, then the water diffuses into a drier layer of the towel, lowering the concentration of the surface layer and allowing it to absorb more water.”
That was a lot of science, I know. But the point is this: Folding a paper towel — and thus, making it thicker — should increase the amount of water it can absorb. “When the guy in the TED Talk mentions interstitial suspension, he’s talking about effectively increasing the thickness of the paper by folding it so that, when the outer layer becomes saturated, water can diffuse into the inner layer, allowing the outer layer to absorb more water,” Klotz confirms. “I suppose the ultimate thickness of a single paper towel would be in the form of a crumpled sphere, but that would probably be smaller than your hand, so I think this guy has it right with a few folds, which would still be bigger than your hand.” Plus, folding the paper towel should allow water to be stored between those folds, which increases absorption even more.
So there you have it: Folding a single paper towel, rather than crumpling a bunch into a ball, seems to be the most efficient choice (I actually just tried this, and it really did work). Go ahead and give it a whirl — at the very least, you can tell yourself you’re kinda helping to save the planet.