When I was researching slime trying to discover a substitute for borax and liquid starch, I learned quite a bit about it.  It found it pretty fascinating, and I thought I'd share some of it here for any folks who might be interested in learning more about how slime works.  Now before I get started, I should mention that it's been MAAAANNNYYY sleepless nights between when I got my minor in chemistry and now, so if you happen to be someone who is actively studying chemistry and I mess any part of this explanation up, please feel free to correct me.  :)

Some interesting slime facts and a scientific explanation for how slime forms and why it behaves the way it does from Fun at Home with Kids

Here are a few interesting things I learned:

1.  All standard slimes are made the same way!

Say what?  Yes.  Seriously.  The storebought slime, the borax slime, the liquid starch slime, and even our laundry detergent slime - they all are created from the same reaction!  I thought this was SO interesting.  Now mind you, there are additional ingredients that vary between each which may result in minor differences between each - but those additional ingredients play no role in forming the slime. 

2.  Slime is formed from just two main ingredients

So how does slime form?  You need two things: polyvinyl alcohol (a main ingredient in washable school glue) and borate ion (which you can get from borax, sodium tetraborate, or boric acid).  What happens is that the polyvinyl alcohol in washable school glue is attracted to the borate ion from borax, sodium tetraborate, or boric acid (depending on whether you are using borax, liquid starch, or certain brands of laundry detergent).  This attraction makes the two molecules form long chains, and tons of those chains together form the slime we love!

3.  Borax and Boric Acid are different molecules, but they both do the same thing in water

Even though Borax (from, well, Borax and also from Sta Flo liquid starch) and Boric Acid (from certain laundry detergents) are different chemicals, in the presence of water they change into Borate Ion.  This is why you add water to borax powder if you are preparing slime using a borax-based recipe.  Sta Flo and the certain laundry detergents that work have water added to them already, which is why you don't need to add any additional water to these slime recipes.

4.  Slime is a non-Newtonian fluid

Just like Oobleck!  This means that it's behavior (viscosity) can change.  You know how when you squeeze oobleck in your hands it's hard and when you hold it gently, it ribbons down?  Well slime has a weird property too - if you stretch it slowly it will stay together, but if you pull it abruptly it will snap/break.

5.  Vinegar will dissolve slime

This was something I tried because I was curious - and it worked perfectly!  I'll admit that I'm not 100% on the scientific explanation for it, but I suspect that the acetic acid (which is what vinegar is made of) disrupts the hydrogen bond (the attraction) between the PVA molecule and the borate ion.

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All activities here are activities I feel are safe for my own children.  As your child's parents/guardians, you will need to decide what you feel is safe for your family.  I always encourage contacting your child's pediatrician for guidance if you are not sure about the safety/age appropriateness of an activity. All activities on this blog are intended to be performed with adult supervision.  Appropriate and reasonable caution should be used when activities call for the use of materials that could potentially be harmful, such as scissors, or items that could present a choking risk (small items), or a drowning risk (water activities), and with introducing a new food/ingredient to a child (allergies).  Observe caution and safety at all times.  The author and blog disclaim liability for any damage, mishap, or injury that may occur from engaging in any of these activities on this blog.


  1. You know the geek in me LOVES this! I will be linking to it in my slime experiment tomorrow! Thank you for being awesome!

    1. Aw, thanks Dayna! I finally got around to hitting publish! YAY!

  2. The nerd in me is so fascinated by this! It's so nice to have a much more clear understanding of it all!!

  3. Love the explanations Asia! I learned so much!

  4. Borax in solution forms boric acid. Boric acid reacts with water to form boron tetrahydroxide ion. It is this ion which forms the cross-links between the polymer miolecules, making slime. Vinegar contains acetic acid, which is stronger than boric acid, so adding vinegar eliminates the boron tetrahydroxide ions from the solution. Without these ions, the cross-links are destroyed and the slime breaks apart.

    1. Really?
      Now I can use this.Whats your name?I 've got to give credit.

  5. thanks.needed this for a school project and we needed an explanation and this was perfect.I won't forget to give credit!!!

  6. I teach science to children and am doing a collaboration video with a fellow youtuber. I am going to use some of your explanation if that's ok? I will give you a shout out of course ;)

    1. That's probably fine unless you'll be using a substantial portion of the content of this post....


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