Two times the slime: Fun with polymers

Author: Maddie Van Beek

Have you ever made goop, gak, or some slimy substance in one of your classes? You probably have at some point! No matter how old you are, it’s always fun to take a break and play with a little slime! But hey, that doesn’t mean you won’t be learning anything! Today you are going to compare two different methods for making slime. 

The first method will use special ingredient: 

• Liquid starch

The second method will use special ingredient: 

• Borax

Both methods use glue and another ingredient to create a polymer. Glue is actually a liquid polymer. The molecules of glue are in separate little strands before you add anything to it. Once you add the special ingredient to the glue, it acts as a binding agent that links all the little strands together to create a more solid polymer, or in other words... SLIME. 



Let’s back up... what exactly is a polymer, anyway? A polymer is a large molecule, or macromolecule, that consists of many repeated subunits. Polymers are created by linking smaller monomers into a chain. Think of the monomers as beads, and the polymer as a necklace made by stringing the beads together. See image below: 

http://images.flatworldknowledge.com/averillfwk/averillfwk-fig12_031.jpg

Below is an example of a polymer. You can see how the same subunit, or monomer, is repeated over and over again. 

http://www.rsccaerodefense.com/images/polymer-cross-linking-repea.jpg

Naturally occurring polymers include cotton or rubber, while other polymers are manmade. Silly putty is one example of a polymer you may have seen before and is similar to what you will be creating today! 



How does each method change the consistency, appearance, feel of the slime? Write down a list of things that you will be looking for to compare one method of slime creation to the other. Create a chart in your observation journal where you can record your findings later. It may look something like this: 

Let’s start with method 1. Then you can make your observations and move on to method 2. 



YOU WILL NEED:

• Measuring cups
• White craft glue (Elmer’s or something similar http://www.walmart.com/ip/Elmer-s-Liquid-Washable-School-Glue-7.62-oz/16828188)
• Liquid starch (Example: http://www.walmart.com/ip/Sta-Flo-Liquid-Starch-64-fl-oz/15028887)
• Mixing bowl
• Spoon
• Optional: food coloring

Here’s what to do!

1. Measure 1/4 cup of the white craft glue and dump it into the mixing bowl. 
2. Pour 1/4 cup of water into the mixing bowl and use the spoon to stir the water into the glue until it looks smooth and well-blended. Write down your observations so far. How does adding water to the glue change it? 
3. Optional: add about six drops of food coloring. 
4. Add 1/4 cup of liquid starch to the mixing bowl and stir it in. How does the consistency of the glue change once you add the starch? Record your observations. 
5. Once you stir the starch in, pick up your slime and play with it! What does it feel like? Look like? Is this what you expected to happen? 

Before you move on to method 2, experiment! 



Extension: Try adjusting the amount of water or glue to see how it changes the quality of the slime. 



Now for method 2!



YOU WILL NEED

• White craft glue (same as method 1)
• Two disposable cups
• Optional: food coloring (choose a different color than method 1)
• Water 
• Borax powder
• Spoon
• Measuring spoons

Here’s what to do! 

1. Measure 2 tablespoons of water and 3/4 teaspoon of Borax and add them into one disposable cup. Label the cup ‘Borax.’ Use the spoon to stir the water and Borax together. 
2. Measure 1 tablespoon of white craft glue and add it to the second disposable cup. Label the cup ‘glue.’ 
3. Add a few drops of food coloring to the glue and stir it in until it is one solid color. 
4. Before you mix the two liquids together, make observations. What does each liquid look like? What do you think will happen when you combine the Borax with the glue? 
5. Dump the cup labeled Borax into the cup containing the glue. 
6. Stir the liquid and watch the slime appear! After about thirty seconds, pull the slime out of the cup and play with it! 
7. Before you get carried away, make your comparisons. How is this slime different from the slime you created in method 1? Go back to the table you created before you started, record your observations for method 2, and make final comparisons between the two kinds of slime. 

Extension: Once again, experiment with your ingredients! Does changing the amount of water or glue in method 2 also change the quality of the slime? What if you add more Borax? How can you make the slime even more stretchy?  




References

https://sciencebob.com/make-some-starch-slime-today/

https://sciencebob.com/make-some-starch-slime-today-method-2/

https://en.wikipedia.org/wiki/Polymer#Common_examples

http://serc.carleton.edu/sp/mnstep/activities/35866.html

http://scifun.chem.wisc.edu/homeexpts/gluep.htm