# Are Clothespins Worth Using?

I've been using clothespins all along. I know other people who do as well, and some who never use them. While discussing this over dinner, it seems there are two stances that people take:

1. Pins are not worth using at all. The clothing dries as fast as it does without them, perhaps insignificantly slower. The time needed to work with the pins does not make up for the benefit of having the laundry done faster.

2. Pins clearly must do a difference as the clothing is just in two and not four layers.

Well, I am clearly in the second team. But this is a hypotheses that one can test and negate. So apply the scientific method! As a setup I took four pieces of underwear and two t-shirts. Then I put half of them on the dryer with pins, the other just folded in half. Every now and then I measured their weight with a kitchen scale.

The following figure shows the raw data. One can see that the t-shirts weigh more than the underwear, which is not surprising. And it seems that it took only around 24 hours for the laundry to completely dry, to reach the dry weight. However, there was still a bit of moisture to be felt. In the clothes without the pins it was just in the middle around the fold. The ones with the pins however had moisture on the bottom, being pulled down by gravity. So even though there was more surface area to diffuse the water from, it would get pulled down there.

In an attempt to compare the different items, I have computed the relative amount of water: $$W(t) = \frac{m(t) - m(\infty)}{m(0) - m(\infty)} \,.$$ The numerator is the water weight, so total weight minus dry weight. The denominator is the total water weight that was present when I started the experiment. So all items start at 1.0 and finish at 0.0. If one method was faster then the other, we should clearly see one below the other. But we don't, so there is no significant difference between the two.

There are two ways to interpret this: Either it just does not make any difference, whether one uses pins or not. Alternatively my method of dryness detection is not precise enough. Either way, the current experiment cannot detect a difference. And if there was a significantly different diffusion rate, one could see that in the early points. I presume that drying has some sort of exponential behavior, and therefore it should not make much of a difference for the last bit of humidity. So at least in the summer it does not make any difference.