Guest post by Molly McCracken
Of 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:
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.
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.
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.
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.
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.
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.
About the Author
Molly 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.