Making Slime – Gross

Tuesday, March 10th, 2015

This post is written by Derek Gallo, a junior at XXX High School.  He is one of the Boeing Scholars.  His team STEM Ed(you)cation is working on science outreach, through a family science night at Darwin Elementary School.

Making slime is a perfect entrance into the world of polymers.  Just a little bit of glue, water, and borax, and you are off to the races!

Materials

  •  - Borax (“20 mule Team Borax” - can be found at store as laundry detergent)
  •  - Polyvinyl Alcohol (PVA)
  •  - Wooden popsicle stick (or something else disposable to stir with)
  •  - Plastic cup or bag for your slime

Procedure:

  1. Dissolve the PVA powder with warm water, 4 grams of PVA for every .1 L of water.
  2. Dissolve the Borax powder with warm water, 5 grams of Borax for every .1 L of water.
  3. Measure 50 mL of PVA solution into a plastic cup or bag.
  4. Then choose a color for your slime and add 2 drops of that food coloring.
  5. Now add 5 mL of Borax solution.
  6. Stir it all together with a wooden popsicle stick and you’ve got slime!

Note: Using a liter of water for the PVA solution will make enough slime to serve 20 people. The slime can last for weeks in the refrigerator, but may mold after a week if left in the open. The slime can be easily washed from clothes with warm water and detergent.

What is Going on?

Slime is simple polymer chemistry. It’s a perfect example of cross-linked polymers. Polyvinyl Alcohol is a long polymer chain of repeating units with an alcohol functional group. Before they get linked in a polymer, the single units are called monomers.  They are small and can slide past each other really easily like a bunch of beads in a bowl. But polymers are long and bulky and can move past each other.  They borax contains a cross-linking agent that starts the polymerization reaction.

Long chain polymers are used in synthetic fabric, plastic, nylon, etc. So next time you put on a T-shirt or use a Tupperware you are using long chain polymers of repeating carbon bonds.


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