Halloween Science: Mad Scientist’s Green Slime

 - by KitchenPantryScientist

What could be more fun than creating your own green slime ?  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.

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