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  • Ow...I think I need some help with my laundry.

  • Hey there, washed and left out to dry. Trace here rockin' some 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, you're really doing 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 our favorite sweater or shrunk a pair of pants. But why do all of 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, 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 molecular structure or anything else. So, let's ignore those.

  • Natural fibers, on the other hand, they come from animals and plants. The fibers of cotton,

  • wool or silk are naturally curly and tangled. So when you want to weave these threads into

  • fabrics, you have to stretch then, and to pull them out to make them straight. But if given the opportunity

  • to return to their natural curly state? They will. And scientists have discovered all that heat

  • and mechanical energy in laundry let them do just that, in a process they call, funnily enough,

  • 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 and manufacturing. That tension exists on a molecular level,

  • and is leftover from that 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 in between them. Water is slippery, so it reduces the coefficient of friction,

  • and those scales then slide together, contracting rootward, like a retracting car or radio antenna! Super cool!

  • 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, causing them

  • to curl back up again.

  • A 2002 study in The Research Journal of Association of Universities for Textiles. found the structure

  • of the fabric can affect shrinkage too. Denim jeans are tightly-woven cotton so they

  • shrink a little, but sweaters, they're mostly air! So they can shrink by as much as 30 percent according

  • to Popular Science.

  • Even the natural moisture content of the fibers themselves can affect the shrinkage: cotton has

  • about 5 percent, and 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. 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. More researches obviously needed.

  • Look, scientists who did write these papers on shrinkage were quick to point out: everyone does laundry

  • differently. Water temperature, amount of time, detergent, clothing fibers, and even

  • machine manufacturer can all add variables to to this at-home science project

  • The best way to love your clothes is to remember that, one, the instructions on the tag is there for a reason

  • the people who made the clothes know how to clean it. And 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 actually kind of okay.

  • Skinny jeans, sweaters, tiny t-shirtswhy am I reminded of hipsters?

  • Oh, because they're all the same! At least, that's what this mathematician discovered! So I did a whole video about it.

  • Grab your fancy coffee and give it a click.

  • Hipsters are difficult to describe as a group.

  • But we know one when we see one, right?

  • And a new mathematical neural science paper explains why that is:

  • The Hipster Effect. When anti-conformists all look the same

  • Do you love laundry? Do you hate it? Are you super meticulous about how things get folded?

  • Let us know down in the comments! Make sure you subscribe, so you get all of the Dnews that we got up in here.

  • And thanks for watching!

Ow...I think I need some help with my laundry.

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B2 中上級

なぜ洗濯すると服が縮むのか? (Why Do Clothes Shrink When You Wash Them?)

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    李宣億 に公開 2021 年 01 月 14 日
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