The Science behind Slime
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The Science behind Slime


This is slime. Super fun to play with, and
it has some cool things to teach us about science. In this video we’ll learn how to
make it and why it works. we’ll also talk about borax. What is it? Is it hazardous for our health or not, and can you make slime without it? Let’s start with taking a closer look at glue. White school glue is PVA glue. That stands for polyvinyl acetate. if you look at the molecular structure, you’ll find long chains of carbons and every few carbons, there’s an oxygen, another carbon, and another oxygen. You see, PVA is what we call a polymer. Just like individual pearls strung together
make a necklace, a few thousand pieces of vinyl acetate strung together make PVA. Besides these long strands of PVA, glue also has a lot of water. All that water
allows the strands of PVA to slide past each other, kind of like a big bowl of
wet spaghetti? Huh? but when the water evaporates, the glue hardens. The strands
of PVA come together, attaching to each other and whatever else they’re
surrounding. There are a few other ingredients in the glue, but we don’t know what they are. What’s in the glue? Can’t tell you. Why not? So that’s glue. It sticks to the table and my fingers, and I can’t gather it together and pick it up. It’s a sticky liquid. If we add this sticky liquid to a solution of borax, it changes almost instantly. Now, I can pick it up. It no longer sticks to my fingers. It’s a
stretchy stiff substance. What happened? It was the borax. Borax is a salt called sodium tetraborate. and when it’s added to glue it bonds to the oxygens in the PVA, linking the long strands together. And when they’re linked together, they
behave very differently. And they don’t flow past each other as well as they did before. If we saturate plain glue with borax, we get a very stiff substance. It’s so stiff, it’s hard to mold and stretch. and this is why, in our classic slime recipe, you add water to dilute the glue before you add the borax. In the classic slime recipe, you’ll mix together 1 part glue with one part water and food coloring. And here, people sometimes make the mistake of not mixing the solution thoroughly. If you have some areas that are more
concentrated with glue and others that are more watery, then your slime will end up having a very strange, uneven texture. So mix it thoroughly. And then you can do one of two things to activate it, Whichever method you use you
will need to make a borax solution, which is made with the ratio of 1 tablespoon of borax powder to one cup of water. Method 1 is to dump your glue mixture
into the borax solution and then lift it out. After you lift it out, spend a minute
or two kneading it together. [ music ] The second way of activating the slime
is to add one tablespoon of the borax solution, and mix. Then add a second
spoonful of the borax solution and mix again. After the second spoonful, you
might be thinking that it’s not working and won’t come together, and you’ll need
to add more borax. But don’t add more borax yet, or your slime might end up being too stiff. take a minute or two to mix it, and then test it with your fingers and see how tacky it is. Then, if you need to, sprinkle a little more
solution over the slime. The texture of finished slime is going to be pretty similar regardless of whether you use version 1 or version 2. And it’s a fantastic substance. It stretches if you pull it slowly, but snaps apart if you pull it too fast. It stretches so thin that you can almost see through it, and it bounces! All of this begs the question,
is slime a liquid or a solid? Well, it’s a special kind of liquid called a non-newtonian fluid. The more pressure you apply to it, the more it behaves like a solid. This is why when you drop on a hard surface it bounces, or if you pull it fast it snaps. But it’s still a fluid. It adopts the shape of its container, and if you leave it on a slope, it will slowly flow and ooze downhill. [ music ] No doubt about it, slime is a ton of fun, and it’s all made possible by the way borax links those polymers together. But is borax safe? Borax is sold in the laundry isle of grocery stores without any safety warnings or restrictions. Table salt is also sold in grocery stores
without any safety warnings or restrictions, and it’s commonly used to make playdough, which millions of children play with every year. Here’s the deal. Toxicity depends entirely on the dose. Too much of anything is too much! Absolutely no table salt in a person’s diet would be fatal. Fatal! Too much table salt in a person’s diet would also be fatal. yet, when used in the right amounts, table salt is perfectly safe and non-toxic. Borax is similar. The amount required to produce adverse reactions has been measured, and it’s quite high. Used in small amounts, it is very safe and
non-toxic. So where did all the concern about borax being harmful come from? Near as I can tell, it happened in early 2017 when a young girl got severe blisters on
our hands from prolonged exposure to slime. Articles ran headlines that borax
posed potential health danger to kids, and borax-free slime recipes started
popping up all over the Internet. In this particular case, the girl spent several hours each day making and playing with slime After several weeks, she developed a mild rash, continued to make slime, and then developed blisters. There are not many things that you should have consistent daily exposure to
over a prolonged period of time. If you have sensitive skin, prolonged
daily exposure to water can cause you to get severely chapped
and irritated skin, and while there have been multiple documented cases of people
having severe skin reactions to frequent hand-washing or to bathing, we don’t see
a correlating response of concern about water safety. There has not been a wave of news headlines asking if it’s safe to take a bath. Nor are we seeing a whole bunch of articles and tutorials for how to clean yourself with dust like a chicken. And it’s worth pausing a minute and asking ourselves why. Why don’t we blame water in this case? Some of the skin reactions that people have in response to daily bathing and handwashing are incredibly severe. But in these cases, we’re quick to blame the circumstances, or some unusual condition the person has, not the substance. We don’t rush to the assumption that water
is dangerous. So why did we do that with borax? Well, maybe because water is
necessary to our health and borax isn’t. Perhaps because we have more evidence of bathing and hand washing being beneficial. but I think it’s also due to
a lack of understanding about chemistry which is illustrated in the next recipe
that we look at. The most popular borax-free slime recipe: contact solution slime. Mix one bottle of glue with a 1/2 tablespoon of baking soda and food coloring. Add 1 tablespoon of contact solution and
voila! We have slime. How is this recipe working? Well, the baking soda increases
the pH of our glue solution and that causes more of the oxygens to react and
to form polyvinyl alcohol and acetic acid. We’re priming the pump so that when we add our borax activator we won’t need as
much of it to get that same cross-linking to occur. Now we can form cross links even easier! Hurray! You might be thinking, wait a minute. contact solution doesn’t have borax in
it. Or does it? Look right here and you will see boric acid listed in the ingredients. For our intents and purposes boric acid and borax are synonymous. They
have virtually identical ratings in regards to safety and toxicity, and the
salt (borax) converts very easily to its corresponding acid (boric acid). If there’s enough boric acid in saline solution to activate slime, and millions of people use saline solution every day with no ill effects, then this is very strong
evidence that boric acid and borax, when used appropriately and in small amounts,
are incredibly safe and non-toxic. And the real question is which slime is
better? the classic slime made with the borax solution from the powder, or this newer recipe made with contact solution? I surveyed several kids, and they almost all agreed that they liked the contact solution slime best. It smells better and it bounces and stretches a little more easily, The only thing that it didn’t do as well as the classic slime was ooze. [ music ] But we fixed that by making what I call
Science Mom slime. I tested dozens of recipes and finally came up with my own tweaked variation. This slime has the perfect balance of ooze, stretch, and bounce. 4 ounces of glue, 2 ounces of water, 1/2 tablespoon of baking soda, and
food coloring. Mix them together. Then add your tablespoon of saline solution and mix. And you might need to add just a few
drops more depending on how tacky your slime is. In my opinion this slime has
the perfect balance of ooze, stretch, and bounce. The best… slime… ever! But what if you want a slime that is even safer than the already safe borax based or saline
solution based slime. What if you want something that’s not just non-toxic but edible? There are a variety of glue-free, borax-free slime recipes out there, andwhile many of them will give you a slime-like substance in theory, in practice what often happens is that you either have a very sticky oozy mess, or you get a dough. It’s very difficult to land in between. but one of the more reliable
glue-free recipes is to mix cornstarch with yogurt. If you experiment with the
ratios here you can often end up with something that is close to slime if you
don’t mind your fingers getting messy, or if you add more cornstarch you end up
with a pretty cool dough. Let’s take our edible slime that is actually
more of a dough, and compare it to our other three slime recipes. The borax and saline
solution slimes all squelch very nicely. The yogurt cornstarch— not so much. Let’s look at stretching and snapping, windows, bouncing, and oozing down a hole. [ music ] Thanks for watching, and thank you to
everyone who requested that I do a slime video. My own kids had a lot of fun
helping me do this video. And if you would like to download a foldable book
that has instructions for how to make each of the types of slime we made in
this video, head over to my website there’s a link in the description down
below, and you can also get some worksheets and coloring pages that talk
a little bit more about non-newtonian fluids and polymers and some of the cool
science that goes along with slime. If you have other topics that you would
like me to address in future videos, let me know in the comments. And as always
work hard, grow smart, and I’ll see you next time. If you store your slime you’ll want
to keep it in a covered container because it will dry out just like the
glue can dry out and over time, it does get just a little bit more stiff
and snappy. So there’s our classic slime after a couple days, and here is saline solution without adding water. It still has nice stretch to it. Snap. And then here’s the Science Mom slime, still quite nice and oozy.
It also hasn’t changed too much after sitting a couple days in a closed container. Oops. Science Mom slime is the best. Ahhhhghhh. It’s eating my hand! Ahhhhhghhh. Just kidding. It oozes down perfectly, and it comes off easily. Ooop! Dont let it touch the ground! Dirt’s on the ground.

100 thoughts on “The Science behind Slime

  1. In the science mom slime recipe can clear glue or glow in the dark glue be used instead of white glue or does it change the mixture ?

  2. Brilliant recipe and super awesome brilliant explainations: Thank you so much Science Mom! Your slime worked first time for me. Now I have stopped flailing around all the unspecific recipes.

  3. The one that you dunked was more slippery and watery than the other one you mixed with borax I prefered the first one

  4. if my teacher finds this video she would say I was plagiarizing but no I put it in my own words like if that's smart 🙂

  5. (1:00) – Did you try looking up the datasheet/datasheets for any particular brand?
    Surely
    there must exist,
    somewhere,
    a datasheet,
    for the basic,
    generic,
    PVA formula?
    No?

    I don't think you looked very hard.
    So long as there are "proprietary" formulas lurking around,
    yes !
    these are the ones to avoid.
    After all,
    it's glue,
    not a beauty or cosmetic product,
    so one,
    us,
    we all,
    have to be uber-careful
    before allowing any kind of skin-contact.

    Come on, Science Mom !

    Is it totally impossible for you to do some fairly easy and basic research?
    Have you heard of the telephone?
    I'm sorry but I'm outta here…
    … and I would put $1,000 that this comment follows me.
    Oh well,
    On your conscience be it…

  6. Science Mom, you are awesome! I shared you on FB and I'm sharing you with my students. Thank you for your explanations!

  7. A quick announcement about comments: When I first started visiting schools I would get a lot of comments saying things like: "Remember me? I'm John Doe from Mitchell Elementary! My teacher is Ms. Smith!" For a while I replied to these comments and then deleted them to protect the student's privacy–but then I came up with a better idea: Now when I do school visits I have the class name some part of the demonstration – then I let them know that if they want to leave a comment, they can reference the name that they chose and is unique to their class. Naming a ball or balloon is a fun exercise and also a good opportunity to talk about internet safety. So if you see things like #Bob or #teamShocky or "Michael the balloon!" and are wondering what in the world is going on? That is what's going on. Also, since many of my viewers and fans are kids, any comments with vulgar language or curse words will be deleted.

  8. While searching the internet for slime recipes, I came across this video and love you! I told my daughter if I figured out how the ingredients worked together I’d be able to help her make better slime.
    I love your science mom recipe 🙂 proves that science moms are best! Thanks for sharing!!

  9. I was wondering why there were all these non borax recipes. I was in school in the 90s and 00s… We diddn't have TidePods, or the Kylie lip challenge then. I used to say "use common sense, but I like your explanation Of "Too much of anything is too much" for explaining things in similar situations. Thanks!

  10. finally someone explained this. i’m interested to know how other ingredients affect slime as well- like cornstarch and shaving foam and foaming hand soap- of course not all because that would take an eternity but it’d be cool to know some

  11. The classic slime dilutes the glue, has more water… so you compromised and added baking soda and half the water! 9:46 Did you mean to say "saline solution"?

  12. No people there are other activators okay not just borax okay you can use liquid starch you can use Tide you can use laundry detergent you can use contact lens solution and baking soda like not just borax you don't need borax clearly I've been making slime more than you have and I don't even use borax

  13. I think you might have made a little mistake you said a special type of liquid it's called a non Newtonian fluid non Newtonian fluid means it's not a solid nor liquid and you call the liquid just a little reminder

  14. The reason that borax became a hazardous substance is because a lot of people said there was bleach in it That's why there are other activators that you can use

  15. The girl probably only got blisters on her hands because she was allergic to borax or the ingredients in it

  16. You know what I think is weird about bathing yourself and dust is that dust is like dirt and stuff but it's also dead skin and that's kind of gross the dust that is coming off of somebody's or your body is what you're trying to wash off in the water of a shower or a bath so why are you bathing in something you're trying to get rid of

  17. We probably thought that borax was bad because it a laundry detergent that you're not supposed to handle now water on the other hand can be dangerous for some people but like you drink water You're going off of topic You're telling me that basically borax a laundry detergent which contains many chemicals is the same as water which is way off of topic they're not the same thing so don't put them close together and don't pretend like they're the same thing because they are completely different

  18. This is exactly what I've been looking for!Don't know how I will manage to finish my project without it.🤗

  19. Hey remember me from Ronzone Elementry Bertha school I was in Ms.Hendersons class when you did the things about the bottles

  20. Can someone please tell me if the science mom slime works with clear glue as well? Thanks!

  21. A friend of mine pointed this out to me since I'm trying to start homeschooling (over the summer). We've been testing out slime and one person actually had pointed out the specific ingredient needed in the contact solution. We tried 2 of them before that and it didn't work. My oldest now knows we needed boric acid but this will help explain to her why and what it does. Thanks for this. Chemistry was a subject I wish I had done more of in my own schooling because it's so cool to explore.

  22. Wow! What a cool channel! Hey, I wanted to point out that skin damage from too much washing and bathing can often be due to the cleansers that are used – antibacterial soaps can cause terrible reactions! I know, because I've experienced them! Thanks for a very entertaining channel!!!

  23. I loved the video. I've waited till' end, and……no regrets. Can't wait to make the perfet slime for my sister

  24. You are talking about artificial slime. Can you do one on real slime please? Thank you for the video!

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