Making borax slime is a fun way for kids and adults to learn about polymers and elastomers. The slime itself is made from white glue and borax. A 4% polyvinyl alcohol (PVA) may be used instead of the glue to make a clear slime that is less rubbery. Food coloring, zinc sulfide, or other items may be added to the borax slime for special effects.
Borax slime is a common activity used by science teachers to explain the difference between polymers and elastomers. A polymer's molecules are not attached so they slide easily past one another, as in the case of liquid glue. When a chemical in borax cross-links, or connects, to the molecules in the glue, an elastomer is created. Elastomer molecules are still able to slip past each other, but remain connected. This results in a stretchy, flexible substance like the finished slime.
To make homemade borax slime, gather a bowl, measuring cups and spoons, a box of borax, a bottle of white glue, water, and a ziploc bag. Food coloring is optional. Borax may be found in the laundry detergent section of a grocery store or supermarket.
Wash your hands before beginning to prevent mold from growing on the slime. Once this is done, mix 8 ounces of water (240 milliliters) and 1 tablespoon (14.3 grams) of borax. This should be stirred until the borax is totally dissolved.
The next step in making borax slime is mixing 2 ounces (59 milliliters) of water and 2 ounces (59 milliliters) of white glue. These ingredients should be mixed until completely blended together. Pour this into a ziploc bag and add 4 ounces (118 milliliters) of the borax and water mixture. At this point, 2-3 drops of food coloring may be added if desired. Seal the bag and knead it until the two mixtures and food coloring are completely combined and have become slime.
Another borax slime recipe substitutes PVA for the glue. This makes a clear slime to which all kinds of interesting things may be added. For example, 1 tablespoon of zinc sulfide can be added to the PVA prior to adding the borax and water mixture. Once kneaded, it will turn into a light green slime. When the slime is ready, expose it to either regular or black light for a minute or two. Turn out the lights to see the slime glow in the dark.
This mixture should be kept in the refrigerator when not in use. It will keep for quite some time, but eventually will dry out or grow mold. Playing with slime over carpeting is not recommended as it may be difficult to remove if it gets on the carpet. This recipe is not edible and should be kept away from small children and pets.