TROUBLESHOOTING HELP If You Have Any Questions About The

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TROUBLESHOOTING HELP

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COURSE CREDIT

Day 3: SLIME!

Supplies: • PVA Glue (Elmer’s or Amazon Basics work well) • Multipurpose Contact Lens Solution containing boric acid • Water • Baking soda • Measuring spoons • Paper or plastic cups (12 oz or larger work best) • Wood tongue depressors or large craft sticks • Food coloring, liquid watercolor, or paint for color • Foil tray or large container for mixing and to contain spills

Slime Instructions

a STEP 1: Prepare ingredients STEP 2: Prepare glue mixture

a. Add 2-3 tablespoons of a. Pour about ½” of baking soda solution to glue into the bottom the glue and mix

of a cup. thoroughly. Mixture

should still be a thick

liquid, not watery.

b. Combine 1 cup of water and 1 teaspoon of baking soda to b. Add desired color make a baking soda and mix thoroughly. solution. Mix thoroughly to dissolve.

STEP 3: Activate slime STEP 4: Hand mixing a. Squeeze some contact a. Touch the slime with one

solution into the glue finger to test the mixture and begin stirring. stickiness. If it sticks to Slime will begin to thicken. your finger, squirt a little bit more contact solution over the slime and fold the slime over a few times to combine.

b. Add another squeeze of contact solution and continue stirring. The mixture will become

very thick and difficult to stir. b. Pick up the slime with your fingertips and continue mixing. A c. Continue mixing, until the stretch-and-fold slime begins to release technique works well. from the sides of the cup, adding more contact c. If your slime isn’t forming, is too sticky, or if it isn’t solution if needed. Transfer to a tray for as stretchy as you want it to be, see the further mixing. troubleshooting tips in the next section

Concept: What is slime?

Most DIY slimes are made using Polyvinyl Acetate (PVA) glue, while commercial slimes are made using

Polyvinyl Alcohol. Both substances are polymers which consist of long strings of molecules called polymer chains. These polymer chains slip and slide around over each other like wet spaghetti, giving them their liquid properties.

Slime is formed through a process called cross-linking. When PVA glue is mixed with a solution of sodium borate, the borate ions link the polymer chains in the PVA together , which causes the substance to thicken and form what we call slime. The sodium borate needed to make slime can be found in a number of household products, including Borax powder, StaFlo liquid starch, and some laundry detergents. In this recipe, we use a solution of boric acid (found in the contact solution) mixed with a baking soda solution. A chemical reaction between the boric acid and the baking soda (an acid-base reaction), produces the sodium borate needed to make slime. (Without the baking soda, slime doesn’t form. Try it!)

Slime is a polymer that behaves as both a liquid and a solid. When force is applied to the slime, such as squeezing it in your hand, it behaves more like a solid. When it is sitting untouched on table, it will spread out like a liquid. (This can be a fun observation activity once the slime is finished.) According to Newton’s law of viscosity, the viscosity of a fluid – how easily it flows – should only vary with temperature. Because slime’s viscosity increases when force is applied, it is considered a non-Newtonian fluid.

TROUBLESHOOTING

My slime is too sticky.

This is caused by excess glue that is not yet crosslinked. Add a little more contact solution and continue mixing. If the slime is still sticky, add a small amount of baking soda solution. Continue mixing and adding small amounts of both solutions until the slime is no longer sticky.

My slime is not forming/is too runny.

Make sure you have added both contact solution and baking soda solution to the mixture. If you have added a lot of contact solution, you may need more baking soda solution to balance it. If these additions don’t help, check the label of your contact solution to make sure it contains boric acid. Also be sure you are using PVA glue. Not all glues are suitable for making slime.

My slime is not as stretchy as I want it to be.

Too much boric acid and baking soda will cause slime to be less stretchy. Adding some watered-down glue (about 1:1 glue/water) will make the slime more flexible. Add a generous amount and mix until the slime reaches the desired consistency, adding more glue/water as needed.

My slime breaks or doesn’t stretch at all.

If the slime is very stiff and watered-down glue isn’t helping, try rinsing the slime in plain water first, then add more glue/water mixture.

My slime is soft and falls apart.

This is usually caused by too much water, or possibly too much contact solution. Add more glue (not diluted) and mix thoroughly. If the slime is sticky after adding glue, add more of the baking soda solution before adding more contact solution.

Help! I got slime on my clothing/carpet/furniture!

You can use white vinegar to remove slime from most fabrics and surfaces. The acetic acid in vinegar breaks the crosslink bonds between the polymer chains, and the slime breaks down to a liquid. Mix 2 parts water and 1 part vinegar in a spray bottle. Spray thoroughly and blot with a towel. For dried slime, soak with vinegar solution for several minutes and then blot to remove.

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