Engineer writes bulletproof rant on why 'over' is the optimal toilet paper position
Tensile strength? Alignment stability? I'm convinced.
The great toilet paper debate refuses to die. Whether to hang the loose end of the roll "over" or "under" has been inspiring heated disagreements for years. Some years, one faction or the other gains ground, but the opposing view never really gets snuffed out. It quietly regroups and comes back with a vengeance when we least expect it, and the toilet paper wars continue on.
Over the decades, many different kinds of experts have been enlisted into the conflict. Psychologists, anthropologists, marriage counselors, and doctors have been asked to weigh in on this debate repeatedly, each bringing a different perspective into why we all have such a strong preference on this topic, and the pros and cons of each.
Now the physical science experts are weighing in. An engineer from BFW Marcum recently unleashed an epic, totally unnecessary, and quite convincing rant about why there's definitively one correct way to orient your TP.
Elya, CC BY-SA 3.0, via Wikimedia Commons
Here's what the engineer had to say about the toilet paper over vs under debate.
"You—the dregs of society that put toilet paper with the flap situated under—you know what you’re doing is wrong," the screed begins. "You must feel it in your bones—some kind of primitive instinctual whispering in your ear. Just look at it—flapping in the breeze of your bathroom like some kind of sad white flag of surrender."
Then we get into the technical, engineer-y reasons that over is supposedly best.
1. Friction Coefficient: The coefficient of friction between the paper and the user’s hand is significantly lower when the paper is hanging over.
2. Tensile Strength: The tensile strength of the paper is optimized when it is hanging over, as the weight of the roll pulls the paper taut. This reduces the risk of tearing and provides a more consistent wipe.
We’ve all fallen victim to pulling off a ragged, possibly too-long length of toilet paper. Not only is it wasteful, but it could also very well ruin your plumbing.
3. Optimal Dispensing Angle: Studies have shown the optimal angle for dispensing toilet paper is between 10 and 15 degrees from horizontal, which is only achievable when the paper is hanging over. This ensures that the user can easily grab the paper and tear it off without awkward twisting or bending.
How do you explain to your peers that your carpal tunnel is not from your desk job, but from the terrible and unnatural way in which you hang your toilet paper?
4. Alignment Stability: When the paper is hanging over, the roll’s natural tendency is to unroll smoothly, reducing the risk of misalignment or uneven dispensing. This results in more efficient use of paper and less waste.
In short, you're more like to get a clean tear, less likely to waste paper, and less likely to get the roll all tangled up with the over method.
Is this all a bunch of gobbledygook, or is this real science? I'm not sure, but either way, it's pretty convincing. It definitely feels like hanging the flap over makes it easier to grab and tear without the roll spinning endlessly, and now I understand (kind of) why that might be.
Lest we actually settle the matter for good, it's worth noting that one physicist interviewed by Vice disagrees and says that, at least when it comes to mechanics, over or under toilet paper is exactly the same.
“Whether you hang toilet paper facing against the wall or facing forward, the rotational kinetic energy you impart on the roll is the same, and it requires the same amount of torque. They’re mirror images of each other, which means the amount of energy you have to expend is the same.” Brian Wecht said. Another physics professor interviewed in the piece more or less agreed, but added that the human element that comes into play is a wild card. The way people approach the roll, whether they're right or left handed, and how much force they apply when they pull and tear, it all factors in.
(I love the idea of highly educated scientists spending their time thinking about problems like this. Did you know that a nuclear physicist once shared a hilarious complex formula to determine if it's better to fold or wad or your toilet paper before wiping?)
Health experts have agreed for years that "over" is also the more hygienic alignment.
Apparently when the flap hangs behind or under the roll, it's harder to grab without accidentally rubbing your hand against the wall. And let's not even talk about the different kinds of bacteria and germs that live on bathroom walls.
Of course, with good hand-washing, this shouldn't be that big of a deal, but it's still a little icky.
The final piece of evidence lies in the original patent for the toilet paper roll, submitted in 1891 by a Mr. Seth Wheeler. You can clearly see that the inventor intended the free end to hang in the front where it would be easy to see and grab.
Public Domain
Ultimately, even if the physicists and engineers and NASA scientists all agree that hanging the toilet paper "over" is slightly better, we're talking about a very small difference in efficiency here. If you like the under method because it looks cleaner or keeps your kids from pulling at the roll, you probably aren't worried about a 1% differential in tensile strength and coefficient of friction.
The scientists might know physics, but they know little of the human heart. If hanging your toilet paper rolls under just feels right to you, don't let these nerds tell you otherwise.