Scientists Just Figured Out How Washing Machines Work?!


[♪ INTRO] There are all kinds of inventions that make
modern living possible, but some fly under the radar. Some so much so that we’ve only just figured
out how they truly work. Case in point: the washing machine. Because apparently, no published paper was
able to totally explain how these things got your clothes clean; not
until 2018. Now, to be clear, it’s not like we had no
idea how these machines worked. The oldest washing machines that resemble
our modern appliances date back to the 19th century, so these things have been around for quite
a while. And for years, we’ve had a really good understanding of how they use soap and detergent to get stuff
off the surface of your clothes. Soap is a surfactant, which is short for surface
active agent. That means its molecules can attach to two
substances that don’t normally interact, for example, oil and water. Usually, one end of the molecule is hydrophobic,
meaning it repels water, and the other end is hydrophilic and regularly
bonds with water. So, when soap is dumped into a big bath of water, the surfactant molecules group together to
form spherical structures called micelles. The hydrophilic ends stick out toward the
water, and the hydrophobic ends hide inside. When a micelle lands on a dirty section of
fabric, the hydrophobic ends pop out and attach to
the dirt, or whatever is soiling your clothes. Then, the hydrophilic ends pull the rest of
the micelle off the fabric’s surface, and the micelle reforms with the soil it’s
“eaten” in its center. Detergents like the ones we use for washing
clothes use anionic surfactants, meaning the hydrophilic end has a negative
electrical charge. But, while there are different types of surfactants,
they generally all work the same way. The reason washing machines spin everything
around is to help the soap solution flow through your fabric and pick up all the
dirt hiding in the crevices. But here’s where the mystery came in: Water
can’t flow through every spot in your clothes. That’s because fabric is usually made of
yarn, which is itself made of multiple fibers. Soap generally has no problem getting into
inter-yarn pores, or the spaces between separate strands of yarn. But it does have a problem getting into intra-yarn
pores, or the spaces between the fibers in a single
strand. These pores are at least an order of magnitude
smaller than the inter-yarn ones, and only about 0.1 percent of the soap solution
can actually get inside them, and even then, it doesn’t get in all the way. Micelles actually get stuck in there and are
only able to move when they’re struck by nearby water molecules. According to the math, all of the micelles
would eventually get knocked out, and that soap and dirt would go flowing down
the drain. But this process would take several hours. And that’s just not how washing machines work. They get the soap and crud off your clothes
in usually under one hour. This phenomenon was called the “stagnant
core problem”, and its what scientists hadn’t been able
to explain until that 2018 paper. In their research, the authors learned that
the solution to getting dirt out of those intra-yarn pores
wasn’t the soap, which is kind of surprising. Instead, it was the rinse cycle, along with
a process called diffusiophoresis. Diffusiophoresis is the movement of colloidal
particles caused by a gradient. In other words, it’s the movement of tiny
particles suspended but not dissolved in a fluid. When you swap out the soapy water with the
clean stuff, the surfactant micelles are way more concentrated
in the fiber pores than they are elsewhere. And when you’re using anionic surfactants,
this creates an electric field that makes the micelles migrate out of those
intra-yarn pores. In their paper, scientists figured this out
by doing a series of experiments. Instead of dirt, they used micrometer-sized,
fluorescent balls, and they picked a standard detergent called
sodium dodecyl sulfate. It also goes by sodium lauryl sulfate, and you can probably find it in most of the
cleaning products you own. The team did one trial with no detergent at all, just to see how much cleaning the water and
agitation could do all by itself. Then, they did a trial that rinsed sudsy fabric
with detergent-filled water, and no diffusiophoresis was observed. Finally, their third run mimicked a regular
wash/rinse cycle, where the soapy fabric was rinsed with clean
water. This time, the team observed that the fabric pores nearly emptied out after just 10 minutes of rinsing, cleaning out the intra-yarn pores over 100
times faster than in the soapy run. So yeah, surfactants get the dirt off your
clothes, but you need clean water to actually get dirt
out of them. This research doesn’t answer all the questions
about cleaning your clothes, for example, why some stains are far more
persistent than others, but it does have some worthwhile applications. With knowledge like this, we might be able
to maximize detergent efficiency and minimize the amount of water and energy
we use to do our laundry. That would make washing machines, both in
your home and in industry, much better for the planet. Which is kind of a big deal, considering how
much water this process takes. On a different note, other research suggests
that faster rinsing speeds could also create a better diffusiophoresis
effect. So there may be turbo-charged washers in our
future that get clothes clean even faster. But, hey. As long as my laundry
comes out smelling fresh, I’m all for it. Thanks for watching this episode of SciShow! If you want to learn more about laundry science, you can check out our episode about fabric
brighteners. Apparently, they don’t just make the colors
in your fabric more vibrant, they make your clothes glow. [♪ OUTRO]

100 Comments

  1. Baruch Hashem said:

    I was told how soap works in 1985 when I was I school.

    Are you saying scientists have gone back to school to learn this stuff?

    September 12, 2019
    Reply
  2. Marisa Crowe said:

    Is this the same foe how hair washing works?

    September 12, 2019
    Reply
  3. YamFestival said:

    More like, scientists are STILL trying to figure out water completely!

    September 12, 2019
    Reply
  4. VKA_CarvedSix09 said:

    The dragonball z have you barely seen it ??? Want to hear a joke allah

    September 12, 2019
    Reply
  5. Hugh Mann said:

    i thought this was a joke.. it was just "useless bait"

    September 12, 2019
    Reply
  6. Laura Willems said:

    Really? Scientists using common sense, go figure. How she said all that with a straight face I don't know. Do better Sci Show!

    September 12, 2019
    Reply
  7. Corbally Cobwebs said:

    Woman goes in, clean clothing comes out!?

    September 12, 2019
    Reply
  8. d 1 said:

    well, duh!

    September 12, 2019
    Reply
  9. Why Google? said:

    She’s probably got a ton of tattoos under that “I’m a boring, good, normal nerdy person” shirt.

    September 12, 2019
    Reply
  10. Max Quagliotto said:

    3:44 – It also goes by sodium yanni sulfate

    September 12, 2019
    Reply
  11. mayonnaise man said:

    Pump the brakes there bud… How are you going to invent a machine and not know how it works, knowing how it works is kinda part of the design process

    September 12, 2019
    Reply
  12. Medicinal Blood said:

    I’m hydrophobic

    September 12, 2019
    Reply
  13. Marie Lastname said:

    Washing machines surely didn't fly under my radar. I was and still very aware of how they are the most important household appliance I have access to. Living without access to a vacuum cleaner? Not even that much of a hassle. Living without a fridge I can use? Would suck but would also be absolutely doable. Living without access to a washing machine? Nope. Nope nope nope. I have washed clothes by hand before and despite it being way less of a hassle than I thought it still was so much work to just wash a bra.

    September 12, 2019
    Reply
  14. Tell Me More About it said:

    I am more curious about what that thing you're wearing is called? Please make an episode about that.

    September 12, 2019
    Reply
  15. Tell Me More About it said:

    So you're saying detergents have sperms in them?

    September 12, 2019
    Reply
  16. Rebekah said:

    More like sodium yanny sulfate, amirite?

    September 13, 2019
    Reply
  17. jcamargo2048 said:

    As a former Industrial Laundry pioneer. I can say that there are so many variables not being taken into account.

    An industrial Laundry washer (Tunnel) does not spin, it just turns from left to right and as it transfers it spins once in order to transfer the load into the following module. Quemical conscentration, temperature, mechanical friction among other things are needed to fully sanitize.

    The only thing holding back the laundry industry is the bleach, it just cant sanitize anything in less than 2 minutes and 40 seconds. Our Tunnels just cant transfer anything faster than that. Many Laundry leaders dont know this and dont even bother to do the proper research and completely ignore this, then they are wondering why they are getting astronomical amount of stain out of the production.

    Conclusion, there is more to laundry than just chemistry.

    September 13, 2019
    Reply
  18. Voodoo Punchie said:

    And then the sperm come out and clean your clothes.

    September 13, 2019
    Reply
  19. The Knave said:

    If you don't know the theory and 'mechanics' of how it works?
    To you, it is the same as magic. 🙂
    (I have this magic box, with a magic window and a scrying board, that allows me to talk to people on the other side of the world and watch moving pictures with sound, too!)

    September 13, 2019
    Reply
  20. DeusWrath Eternus said:

    I bet they don't know that water alone can clean ur hands. Even without soap water alone cleans ur hands pretty well.

    The sky is blue. 🍊 are orange. Gravity is caused by mass heat is caused by fire or excited molecules.

    I honestly need a job at that lab cuz those guys are idiots

    September 13, 2019
    Reply
  21. Zak6959 said:

    Too much information, if you wash your face you can wash clothes.

    September 13, 2019
    Reply
  22. Brian Elton said:

    Is it me or was this entire video just common sense. I mean, who knew that you needed to rinse after washing? Oh wait. Every one knows.

    Seriously, how much money and time was spent on finding out how soap works? Large words aside, I knew everything that video said.

    September 13, 2019
    Reply
  23. Dom Quixote said:

    Poooow mind blown

    September 13, 2019
    Reply
  24. Joe Blow said:

    Think she needs some toner face is looking a little shiny either that or cut back on the greasy foods and makeups

    September 13, 2019
    Reply
  25. Batscat said:

    Man or woman is the question.

    September 13, 2019
    Reply
  26. Greg Orcutt said:

    I can't watch her. Why does she have a ring through her nose? She looks like a cow.

    September 13, 2019
    Reply
  27. President of the Secrete Sankcake Server said:

    Finally, an area of applied stem sciences women will actually start entering the field for!

    September 13, 2019
    Reply
  28. magzire said:

    Friction

    September 13, 2019
    Reply
  29. Christopher Holley said:

    She always looks so grimey

    September 13, 2019
    Reply
  30. Bull Sigh said:

    Why does it seem so obvious now?

    September 13, 2019
    Reply
  31. Jrrz Jnz said:

    I just had a conversation about this a few weeks ago. Creepy.

    September 13, 2019
    Reply
  32. Napoleon IV said:

    They should’ve just asked my mom…

    September 13, 2019
    Reply
  33. Eric Thomas said:

    You’re glowing

    September 13, 2019
    Reply
  34. Banana Phone said:

    WTF you talking about? Washing machines don't clean clothes very well at all, at least not modern ones. I have literally taken "clean clothes" straight from a modern and new washing machine, then proceed to "spill" some isopropyl alcohol on them (91%) and find that the alcohol brings back the true color of the fabric and the rest of the fabric is actually still dirty. This discovery and the repeated replication (using many different washing machines) with similar results has led me to believe that modern washing machines suck at cleaning clothes. The best they can do is fool the user into believing that clothing is "pretty clean". Washing the same items multiple times doesn't seem to make any difference.

    September 13, 2019
    Reply
  35. tyerek smith said:

    So nobody going to take notice that the old washing machine says "Woman's friend"? the feminist and snowflakes hasn't seen this video yet that's why it's still up.

    September 13, 2019
    Reply
  36. SlimJones said:

    So we sent probes to Jupiter but we couldn't figure out how we got pasta off my $10 H&M shirt. Great

    September 13, 2019
    Reply
  37. Rod Diaz said:

    As a former laundry engineer I appreciate the explanations in this video. Much appreciated!

    September 13, 2019
    Reply
  38. Baruch Ben-David said:

    How does a washer work? Put quarters in it. Duh.

    September 13, 2019
    Reply
  39. aKa Donut said:

    Oohhh.. so the woman who threw her child into the washing machine a while ago was a scientist. Ok, makes sense.

    September 13, 2019
    Reply
  40. Daemon Hauyer said:

    These scientists must be millennials.

    September 14, 2019
    Reply
  41. Grimbeard said:

    0:28 How can that early washing machine be a "Woman's Friend"? It doesn't even have a fast spin cycle.

    September 14, 2019
    Reply
  42. Matthew Trzcinski said:

    So… use rinse water the stuff that goes into the detergent cycle?

    September 14, 2019
    Reply
  43. Aynge Mackay said:

    …so I can stop using Tide?

    September 14, 2019
    Reply
  44. Austin Martín Hernández said:

    so engineers beat the scientists

    September 14, 2019
    Reply
  45. Austin Martín Hernández said:

    those molecules looked like double sperms

    September 14, 2019
    Reply
  46. lombardo141 said:

    Really ? 😑

    September 14, 2019
    Reply
  47. M Sena said:

    🐮👃💍 Why?

    September 14, 2019
    Reply
  48. Johnny Alfredsson said:

    I prefer sodium yanny sulfate in my detergent.

    September 14, 2019
    Reply
  49. Anchan Sony said:

    I just got brain washed

    September 14, 2019
    Reply
  50. Chris Miles said:

    … and now their labs smell much better?

    September 14, 2019
    Reply
  51. Nekminute said:

    Turbo diesel charged washing machines lets go !

    September 14, 2019
    Reply
  52. fmxman1564 said:

    Wow

    September 14, 2019
    Reply
  53. Stinky McCheese said:

    Now if they could only figure out what happens to the other sock.

    September 14, 2019
    Reply
  54. Dlanod1234 said:

    👌🏻

    September 14, 2019
    Reply
  55. Mike Meyer said:

    I bet she’s a freak in bed lol

    September 15, 2019
    Reply
  56. Mikey said:

    Did she say “advenchurins” in the beginning?

    September 15, 2019
    Reply
  57. amber rocheleau said:

    Im sorry what?

    September 15, 2019
    Reply
  58. 123pradipta said:

    Well, this is not exactly a criticism. I like video most definitely. But ….. Would you please tone down your make up a bit …. I don't think you wore this much in other videos.

    September 15, 2019
    Reply
  59. Amna Sarmad said:

    Washing machines last longer with calgon!

    September 15, 2019
    Reply
  60. Erik Lunden said:

    0:26 ‘Woman Friend’. Ah, the good old days.

    September 15, 2019
    Reply
  61. Alister Puddifer said:

    I never expected this video to be relevant to abiogenesis, but there you have it.

    September 15, 2019
    Reply
  62. kiraPh1234k said:

    "So surfactants loosen the dirt from your clothes, but you need clean water to wash the dirt away. "

    This isn't novel, this is the basics of how surfactants/soaps work. You have a chemical structure that helps move particles by 'integrating' them in some way, but you still have to move the integrated substances and added chemicals aways. Luckily we also design those chemicals to do similar 'intergration' with water and so we can simply use water to help rinse everything away after.

    I any cleaning involving soaps/surfactants, if you're not rinsing then your doing it wrong.

    September 15, 2019
    Reply
  63. Mayurapriyan S said:

    Diffffusiooooo! Spell for next Harry Potter movie!. It can instantly make your clothes clean.

    September 15, 2019
    Reply
  64. Dicky Strike said:

    Главное, цак не забыла надеть

    September 15, 2019
    Reply
  65. R'hllor said:

    Hey lady! You're beautiful!

    September 15, 2019
    Reply
  66. Ricardo No said:

    yeah but where do my socks go?

    September 15, 2019
    Reply
  67. Elijah Desch said:

    Sodium Yanny Sulfate is was cleans your clothes along with water!

    September 15, 2019
    Reply
  68. DanielSangster said:

    Well now I’ll always press the extra rinse button on my washer

    September 15, 2019
    Reply
  69. Mei said:

    scientist 1: I have no idea how this works
    scientist 2: did you try making it glow?
    scientist 1:

    September 16, 2019
    Reply
  70. William Saltzmann said:

    Get the ring out of your face.

    September 16, 2019
    Reply
  71. cgarzs said:

    0:03 – "There are all kinds of inventrens"

    September 16, 2019
    Reply
  72. Englandsbestlover said:

    Soooo….I’m lost 🤷🏻‍♂️

    September 16, 2019
    Reply
  73. Madara Uchiwa said:

    Ok

    September 16, 2019
    Reply
  74. Madara Uchiwa said:

    "Woman's friend"😂

    If any girls are watching this, go do the laundry! Lol

    September 16, 2019
    Reply
  75. Jessie DeVore said:

    How does soap get rid of oily skin?

    September 16, 2019
    Reply
  76. shane said:

    only 45 seconds in and I'm dumbfounded to hear her say "we" as a race don't know. maybe the University bubble has no idea but engineers have quite an understanding. We also don't know how cars work either ffs.

    September 16, 2019
    Reply
  77. shane said:

    this lady obviously has never washed anything by hand.

    September 16, 2019
    Reply
  78. pauljs75 said:

    The only thing from current cleaning tech they haven't added yet is ultrasound. But yeah, a good rinse cycle does make some difference.

    September 16, 2019
    Reply
  79. thetommantom said:

    I wash my clothes in 5 gallon buckets.

    September 16, 2019
    Reply
  80. Ele said:

    I got a washing mashine ad on this video

    September 16, 2019
    Reply
  81. KCNusach said:

    Putting the pregnant girl on to talk about domestic chores — Scishow fighting gender stereotypes every day.

    September 16, 2019
    Reply
  82. Krishna Shukla said:

    Is this a She male or a trans gender?

    September 16, 2019
    Reply
  83. Paul Skopic said:

    Has AOC ever heard of a washing machine?

    September 16, 2019
    Reply
  84. Thabang Tukule said:

    I worked at laundry, so I mustn't put to much soap?

    September 16, 2019
    Reply
  85. nmeunier said:

    Two ads before the video plays. Sheesh!

    September 16, 2019
    Reply
  86. Rizky indra Pratama said:

    What happen at the past when there is no detergen??
    When there is only a river..
    Cmon.. 🙃

    September 16, 2019
    Reply
  87. Techn9cian123 said:

    Man, she’s frumpy

    September 16, 2019
    Reply
  88. shingshongshamalama said:

    Clickbait? Really?

    September 16, 2019
    Reply
  89. CLardPercussion said:

    Cool shirt. Looks kinda old Westy with a modern collar.

    September 16, 2019
    Reply
  90. Кирлджифук Стан said:

    And i got an add for vashing machines at the beginning

    September 17, 2019
    Reply
  91. Martimus Prime said:

    There. I watched it. Now stop shoving it in my face YouTube.

    September 17, 2019
    Reply
  92. Jake Johnson said:

    this girl is so ugly it's hard to listen

    September 17, 2019
    Reply
  93. David Mcguire said:

    I with no degree figured this out by myself years ago. in layman's terms of course but still that's exactly how I thought it worked what the hell have these "scientists" been doing this whole time?

    September 17, 2019
    Reply
  94. Abdul Aziz said:

    Inventor : let's build a cloth washing machine
    No body : how'd that wash clothes ?
    Inventor: let's just build it, we'll figure that out any other day.

    September 17, 2019
    Reply
  95. David Berg said:

    The ring in the nose was too distracting to get a clear understanding of the information.

    September 17, 2019
    Reply
  96. Lief Couillard said:

    How a washer gunna be turbo

    September 18, 2019
    Reply
  97. nohsara said:

    I dont get it, doesnt all this also apply to handwashing? Not just washing machines?

    September 18, 2019
    Reply
  98. Steven m said:

    Can you drop this woman? She's so dull.

    September 18, 2019
    Reply
  99. Cestélle said:

    I can't imagine that any sort of improvements born out of this information will be in many people's homes for at least another 20 years. Washing machines tend to be a rather long-term investment… unless more of them start blowing their lids off again, I suppose.

    September 18, 2019
    Reply
  100. Scott Paterson said:

    Lesbians

    September 18, 2019
    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *