Polymer Challenge

Students learn about polymers and use the scientific method to test variables to make the bounciest Silly Putty Slime.

Engage

Do disappearing water in cup with polymer trick

talk about polymers and how sodium ions in diaper crystals attract water into the polymer

Explore

Make instant snow

1. extract sodium polyacrylate from two diapers
2. put in cup
3. add cup of water
4. stir to make instant snow

Demonstrate making Silly Putty Slime

Glue:BoraxINWater ratio of 1:1

demonstrate liquid properties by allowing to settle into a container

demonstrate solid properties by pulling and breaking slime

Elaborate

Challenge to Make Bouncier Silly Putty Slime (https://www.teachengineering.org/sprinkles/view/cub_creepysillyputty)

Provide

Each group needs:

• 4 plastic spoons
• 1 bottle of saturated Borax® solution
• 1 bottle/tube food coloring (any color)
• 1 bottle of water
• 1 bottle of 2:1 Elmer's® glue/water solution
• 4 plastic cups
• paper towels

For the class to share:

• 1 box of small plastic zipper bags

Procedure

Making Silly Putty - Instructions from https://www.teachengineering.org/sprinkles/view/cub_creepysillyputty

Instructor note: students make small batches of different mixtures to create a variety of putties. Do not hand out supplies until steps 4 and 5, listed below.

1. Show students the four ingredients they will be using for their putty: food coloring, water, Borax solution and glue solution. Tell them they only get one bottle of each ingredient, so they should use it wisely.
2. Tell students that each batch of putty they make should consist of exactly four spoons of liquid, the ingredients of which are distributed any way they choose. For example, they could try one spoon of glue, one spoon of Borax, and two spoons of water. Tell students they should use two drops of food coloring per batch.
3. Tell students that their goal is to make putty that is very elastic, but not super sticky. (Note: to describe "too sticky," tell students their putty should easily peel from the sides of the cup or even their hands. It should have a consistency similar to cookie dough that easily comes off of waxed paper, not peanut butter that must be scraped off.)
4. Pass out paper to each group. Instruct them to draw a line down the center of their papers and label the left side: Trials, and the right side, Results.
5. Inform students that the best way to mix the putty is as follows:

• Decide on a recipe to try consisting of four spoonfuls of available ingredients.
• Write down the recipe (the ingredient and the number of spoonfuls) they will be mixing on a blank piece of paper. Have students call their first recipe Trial 1 (followed by Trial 2, Trial 3, etc.)
• Put the two drops of food coloring and pre-selected amount of glue mixture that they determined they will use for each recipe/test into a plastic cup and mix well.
• Next, add water and mix well.
• Add the Borax mixture and mix until a solid forms.
• Scrape the solid off the spoon and put it back into the cup and mix thoroughly again three times. If liquid remains in the bottom of the cup after three mixes, take out the solid part and have them mix it with their hands until it is no longer wet.

6. Have students describe the silly putty consistency on their papers (under Results). Specifically, report on each batch's texture: too elastic, perfect, too sticky, etc.
7. Repeat steps with a new recipe. Wipe off and reuse the spoons, but get a new cup for each different recipe. They have a maximum of four recipe trials.
8. Have students try several recipes, again trying to create a putty that is elastic but not sticky.
9. Have students show their most elastic putty to the class, and have them describe their recipes.
10. If desired, offer zipper bags to students who wish to save their putty to take home. Remind them to "zip" their bags because the putty dries out quickly.

Evaluate

bounce putties and see which bounces highest.
ask where else polymers could be useful - self-watering plant soil, erosion control