I think I need help with my laundry.
Hello washed and left out to dry, Trace here rockin' new duds on DNews.
You might think science is something only done in labs, but every week-or-so chances
are you suspend organic and synthetic fibers in a solution of water, enzymes, surfactants,
and detergents to confine particulates and relax molecular bonds.
In layman's terms: you do laundry, and when you think about it, it really is like controlled
chemistry!
Unfortunately, we don't all do this at-home science in the same way, which is why when
doing laundry, we've all messed up a favorite sweater or shrunk a pair of [pants?] but why
do these things shrink at all?!
What's going on there?
So, firstly, there are a couple kinds of fibers used to make clothing: synthetic and natural.
In general, synthetics are man-made polymers like polyester, rayon, Kevlar, or acrylic.
Their fibers are strings of petroleum-based chemical chains.
Synthetics made from petroleum products don't typically shrink in laundry because the washer
and dryer do not get hot enough to mess with their structure.
So, let's ignore those.
Natural fibers, on the other hand, come from animals and plants.
The fibers of cotton, wool or silk are naturally curly and tangled.
When you want to weave these threads into fabrics, you have to stretch and pull them
to make them straight.
But if given the opportunity to return to their natural curly state they will.
And scientists have discovered the heat and mechanical energy in laundry machines let
them do just that -- in a process called shrinkage.
There are three kinds of shrinkage: Relaxation, Felting, and Consolidation.
Relaxing is the immediate release of that stretching and pulling tension left behind
from the straightening of the natural fibers.
That tension exists on a molecular level, and is leftover from the manufacturing process.
When tepid or warm water is added to the natural fabric, the warmth will let the fabric swell,
reducing the size by about 1 percent.
Not too shabby.
Felting shrinkage is when the fibers themselves actually get shorter.
If you magnify wool in an electron microscope it's made of tiny scales, just like human
hair.
According to a paper in the Textile Research Journal, the heat from the washer can expand
these scales letting water get between them.
Water is slippery, so it reduces the coefficient of friction, and those scales slide together,
contracting rootward, like a retracting car or radio antenna!
The third type is Consolidation shrinkage, and it happens in the laundry process itself.
The mechanical bouncing action of your washer and drier beats up the fibers, curling them
back up again.
A 2002 study in The Research Journal of Association of Universities for Textiles.
found the structure of the fabric affects shrinkage too.
Denim jeans are tightly-woven cotton so they only shrink a little, but sweaters are mostly
air!
So they can shrink as much as 30 percent according to Popular Science.
Even the natural moisture content of the fibers themselves can affect shrinkage: cotton has
about 5 percent, wool has about 17 percent, so over-drying can will inevitably cause clothing
to change shape.
In World War II, Nazi scientists added plastics to wool to fill in the spaces and solidify
the fibers, sometimes, and today this continues with manufacturers weaving in non-shrinking
synthetics, and chemists inventing new anti-shrinking agents to cover natural fibers and keep them
from curling up.
Look, scientists who did write papers on shrinkage were quick to point out: everyone does laundry
differently.
Water temperature, amount of time, detergent, clothing fibers, and even machine manufacturer
all add variables to to the at-home science project that is laundry.
The best way to love your clothes is to remember: one: follow the instructions on the tag because
the people who made it know what's in there and how to clean it, but when in doubt don't
add heat and mechanical energy.
Use cold water and avoid the dryer.
And two: remember that natural fiber clothing is made from the parts of living things!
Living things aren't supposed to last forever.
And that's okay.
We'd like to take a second and thank our sponsor for this episode: AT and T. AT&T Digital Life
smart home security helps keep you connected to your home, so there are no more what ifs.
Skinny jeans, sweaters, tiny t-shirts…
why am I reminded of hipsters?
Oh, because they're all the same!
At least, that's what this mathematician discovered!
I did a whole video about it here, so grab your fancy coffee and give it a click.
Do you love laundry?
Hate it?
Super meticulous about it?