What could be more fun than creating your own green slime to play with? It’s easy to synthesize your own green goo using only Elmer’s glue (the non-washable kind), Borax (found in the laundry detergent section of Target and some grocery stores), green food coloring and water.
Mix together about 1/3 cup glue and 1/3 cup water with a spoon or Popsicle stick. These measurements don’t have to be exact. Add a few drops of green food coloring and stir.
To make the Borax solution, add around a cup of water to a jar. To the water, add about a Tablespoon of Borax. Shake or stir to dissolve as much of the Borax as possible. You’re making a saturated solution, so it may not all dissolve!
Here’s the fun part: Add a teaspoon at a time of the Borax solution to the glue/water mix. After each addition, stir the mixture. You’ll see long strings begin to form and stick together. Keep adding Borax until the mixture doesn’t feel sticky. It will form a shiny playdough-like substance. If you add too much Borax solution, it will feel wet, but you should be able to squish it around in your hands to absorb the extra water! The slime isn’t toxic, but Borax is soap, so don’t eat it!
What happens? Mixing Elmer’s glue with water forms a substance called a polymer, which is a long chain of molecules, sort of like a string of pearls. (A molecule is the smallest amount of a specific chemical substance that can exist alone, like H2O, a single water molecule). The polymer formed by water and glue is called polyvinyl acetate.
The Borax solution (sodium tetraborate) is a cross-linking substance that makes the polymer chains stick together. As more and more chains stick together, they can’t move around and the goo gets thicker and thicker. Eventually, all the chains are bound together and no more Borax solution can be incorporated.
You can store the slime in plastic bags. If you want to make a larger batch, just remember to mix equal amounts of glue and water and then add as much Borax solution as needed.
Although I don’t usually do product reviews, when Steve Spangler Science asked me to try out Larry’s Polymer Lab, I couldn’t resist. I’d seen some of Steve’s Halloween Science Demonstrations online and guessed that his kit would probably be both fun and educational.
When the package arrived, we unwrapped a clear paint can filled with 5 different polymer substances in smaller containers (and a big lizard named Larry.) The kids couldn’t wait to get started.
The only polymer we’d played with before was “Mad Scientist’s Green Slime,” made with glue, water and Borax. The kids know that polymers are long chains of molecules, like beads on a string, but Larry’s Polymer Lab’s instruction manual told us that the polymers we were about to play with were super-absorbant and could soak up mind-boggling amounts of water. We put down some newspaper on our kitchen table and opened the can.
As a note, the polymers we experimented with are considered safe, but I would not use the marble-like ones with small children, since they look like candy and are choking hazards. My 11,9 and 5 year olds were perfect ages for the kit.
First, we tried the Water Gel. “When you add water to this superabsorbent polymer, it instantly turns from a liquid to a slushy solid.” The kids were impressed as the water seemed to magically solidify, and it was a good way for them to practice measuring!
Next, came Jelly Marbles, “tiny 3 mm spheres that, when soaked in water, grow into 20 mm water-filled marbles.” The kids loved these and the color component of the experiment adds some fun variations to play with. We want to try growing plants in them!
The Gravi-Goo, “fascinating goo that finds a way to flows uphill,” was neat, but really hard to clean up. My kids always find a way to spill.
Giant Orbs, “gooey bouncing balls turn into massive, colorful spheres after soaking in water” were our favorite! They grow up to 11 times their own size in water over 6 or so hours and the kids played with them for days, checking them every time they came into the kitchen.
We’ve tried “Insta-Snow” before, but the snow-like polymer in this kit worked spectacularly well. My 5-year old asked for more of it for Christmas, not realizing that we still have a ton left over.
At $44.99, the kit seems a little pricey, but it contains enough of each polymer (at least 50 giant orbs and hundreds of jelly marbles) to do the experiments over and over again, use them for a birthday party, or even a classroom science project or party. I’ve started doing science experiments at my kids’ school holiday parties as a change from the usual arts and crafts. Many of the polymers also have a number of suggested variations on the basic experiments.
As I type, Larry the lizard is soaking in a bucket of water. What I thought was just a plastic lizard is actually made of water-absorbing polymer and will grow into a giant, slimy chameleon. What could be better than that?
The kit was sent to me free of charge, but I wasn’t paid to review it. The kids and I give it two thumbs up.