Kids, you all know what Slime is, right? Did you know that you can make your own slime at home? Slime is made by reacting just two compounds or ingredients. One is a long chain molecule, a polymer called polyvinyl alcohol (PVA). This is crosslinked with a simple solution of borax (sodium borate). Crosslinking means that the long chains are joined to each other at a few points along the chain. Such a process makes the molecules so heavy that they are no longer soluble in water, and a gel begins to form.
Please note: All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.
If your adult partner has special access to the following chemicals, a great slime can be made. Add a drop of food coloring to a 4% PVA solution in water in a styrofoam cup. Add an equal volume of 4% borax (Na2B4O7 .H20), and stir the gel with a wooden tongue depressor or ice cream bar stick. Commercial Slime (Mattel) is made by crosslinking guar gum with borax. A polyvinyl alcohol/sodium borate "slime kit" (AP1829) can be obtained from Flinn Scientific, Inc., P.O. Box 219, Batavia, IL 60510 for $2.85. (Sorry, only school order forms or teachers using school letterhead can be used to order from Flinn). "Natural Wonders" (a store in Fox Valley Mall) also sells something called "Professor Wacko's Slime Chemistry Kit" for $29.95.
Your slime can be kneaded into an elastic, semi-rigid glob that has highly physical properties. If the gel is simply suspended from your hand, it will flow and stretch. It can also be stretched by slowly pulling, but it will break if pulled quickly. When placed in a container the gel assumes the shape of the container. Similarly, it will flow into a film on a flat surface. Because of these physical properties, slime is one example of what is called a non-Newtonian fluid.
Well, go ahead and squish away! Read the references below for lots more info.
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Kathleen Carrado Gregar, PhD, Argonne National Labs
[email protected]
May 1994
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References: (1) J. Chem. Ed. 1986, 63, 57; (2) J. Chem. Ed. 1993, 70, 893; (3) Chemical Demonstrations: A Sourcebook for Teachers, ACS, Washington, D.C. 1987, 2, 95.
