Guest Post: How to Make Gooey, Slimy, Icky (& Wonderful) Gak

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I am excited to share a series of guest posts with you by other Artful Parents and teachers while I step back from the blog a bit this month! I hope you enjoy the new perspectives, different ideas, and fresh energy that each brings to this space. And I encourage you to leave a comment to continue the discussion, add your own viewpoint, or simply say thanks!

Guest post by Molly McCracken

How to Make GakOf late, my son’s very favorite activity is playing with cornstarch and water.  He can sit with a bowl for hours and fiddle with the messy goo.  Cornstarch is a great science experiment (learning about a non-Newtonian liquid/suspension that acts almost as if solid and liquid) and can also be used for many great art projects (driveway paint, chalk).  However, it is rainy today, we have no cornstarch in the house, and I wanted something to keep him occupied for a few moments.  I knew that there was some sort of similar experiment with Borax, which we have in the basement, so I decided to see if we had the rest of the ingredients needed to make something interesting.

Quick internet search (thank you Steve Spangler Science) and we have the recipe for Gak.

How to Make Gak

The ingredients are easy to find and the experiment is simple and pleasing.  Here is how we did it:

How to Make Gak
1. Empty an 8 oz bottle of Elmer’s Glue into a bowl.  My 4 year old got tired of trying to squeeze it through the small hole so we took the whole lid off and dumped away.

How to Make Gak

2.  Then we filled the empty bottle with warm water and some silver liquid watercolor, swished it around and that went into the bowl with the glue.  After a bit of stirring with a spoon, the silver wasn’t visible but when I asked my son if he wanted some other color he said “no”.  Alrighty, then.

How to Make Gak
3. We mixed one teaspoon of Borax into a half cup of warm water and added that to the glue.  Almost instantly the mixture started congealing in a very gross way (“It feels like an alien head!!”).  The grossness was extremely appealing to my boy.

How to Make Gak

4. I took the slimy part out of the excess water and plopped it into another bowl, where my son has been playing with it happily ever after.

How to Make Gak

While he was playing I took the time to read him the “why” behind the experiment (from the Steve Spangler website), but I think I lost him at “molecules”.  At least he is getting the idea that science is fun and experimenting can lead to some interesting results. I’m not sure if this Gak will have the same longevity as the cornstarch but at least it is keeping him occupied this rainy afternoon.

How to Make Gak

A couple of days later we made Gak again with my daughter because she wanted her own (though the recipe makes enough for several kids to play with).  This time my son used a good squirt of gold liquid watercolor (yes, we have three large bags of Gak now) and my daughter used a small amount of green tempera paint.  The tempera paint made a nice pale green color but the metallic liquid watercolors really didn’t add any color or shimmer at all.  If you want your Gak to be colored, I recommend tempera paint or food coloring (as the recipe suggests).  Liquid watercolor with an actual color might work as well, but don’t waste the metallics on this project.

How to Make Gak

Happy experimenting!

P.S. Want more science? Here’s my current collection of fave artful kids science experiments

How to Make GakMolly McCracken is a jack-of-all-trades, domestic engineer, lover of trees, and figure-er-outer who likes to make huge messes – in the name of art, science and food – with her three kids (and the moral support of her husband). She occasionally blogs at Cygnet Small.

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  1. says

    Love it, Molly! The gooier the better around here. Although I do recall an incident (not one of my prouder mommy moments) where I left my 2 and 5 year old unsupervised (for just a few minutes; they seemed so happily occupied after all) with their gak. Upon my return I found a good portion of it well-infused into my 2 year old’s curly locks. Mind you, these were highly treasured, as yet to be cut curly locks, so this was fairly traumatic for me! We did manage to remove it without having to cut it out, but it was a VERY arduous process, so TAKE HEED….have a blast with gak, but WATCH them, so they don’t put it in their hair!!! Thanks for a great post, Molly!

  2. erin says

    I also recommend keeping it away from children’s hair – we ended up cutting many inches of hair after one gak-hair episode :( Otherwise, super fun for kids!

  3. Julie Liddle says

    Another cool thing to try with this stuff with the slightly older ones is using it for cutting practice. I think it would be very satisfying to snip through it with scissors while working on mastering that cutting motion.

  4. Lori N says

    Made some this afternoon after reading this post. My 3 and 5 year old boys LOVED it.
    BTW, my 3 year old did put some in his brother’s hair, but I brushed it immediately and it all came out.

  5. says

    Gak is really fun, sometimes in my childcare program we have add markers to the table with it. It’s really fun to draw on. That’s usually day two with it.

  6. Ann says

    We love this activity at our house. And after a call to poison control after my 18 month old ate some, I learned it’s not toxic (phew).

  7. says

    Hmm, good question. It is marketed as an all purpose cleaner and laundry booster. I’m not sure what might replace it. I’ll look and see if I can find an answer to that! :)

  8. says

    Just did a quick search and washing soda might work. I haven’t tried it, but might have to. Baking soda was also suggested as an alternative to Borax, not sure if that would work though. Would be good practice in hypothesizing and using the scientific method! :)

  9. Tam says

    Hi to any Aussies, I just got Borax at Coles in the household cleaning section.
    The guy at the checkout was amazed, he’s a teenage science enthusiast and I think he was going to buy some after his shift at work.

  10. says

    How is this not toxic? I use borax whenever I’m doing DIY pest control around the house. Granted the lethal dose is about 2g/kg, meaning it would take a lot to kill a child, I would imagine it could make them sick