Placeholder Image

Subtitles section Play video

  • 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.

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B2 US laundry shrink wool natural washer clothing

Why Do Clothes Shrink When You Wash Them?

  • 6248 498
    李宣億 posted on 2016/07/04
Video vocabulary