Investigating Polymers: Comparing Two Liquid Glue Based Polymers
In this experiment, students will work in small groups to create two different polymers, similar to Flubber and Silly Putty, using Elmer's glue, liquid laundry starch, and Borax. They will then compare the properties of the two polymers. Students will record their observations of the glue and liquid laundry starch or Borax solution before they are mixed and after they have been combined.
The students will understand that a polymer is a long chain of molecules.
The students will give examples of physical properties.
The students will make observations of the properties of the two polymers.
Vocabulary: polymer, molecule, variables, physical properties, elasticity
Context for Use
Resource Type: Activities:Lab Activity, Classroom Activity
Grade Level: Intermediate (3-5)
Description and Teaching Materials
Elmer's or other liquid white glue
Liquid laundry starch
Small plastic cups (4 per group)
Straws or craft sticks for stirring (2 per group)
Before beginning the experiment, review properties of matter. Students should have a basic understanding of molecules and polymers.
Polymer One (glue and liquid laundry starch)
1. Pour 1 teaspoon of glue into one cup. Pour approximately 3 tablespoons of liquid laundry starch into another cup. Students should record their observations of the two liquids in their science notebooks.
2. While stirring with the craft stick, slowly add the liquid laundry starch to the glue until it forms a glob.
3. Remove the glob and knead it. Excess starch may be patted off with a paper towel.
4. Students should stretch and manipulate the polymer, then record their observations in their science notebooks noting how the properties have changed.
Polymer Two (glue and Borax solution)
1. Create a saturated Borax solution in one cup by mixing 2 teaspoons of water and ¼ teaspoon Borax. Stir until as much Borax dissolves as possible.
2. Place 1 teaspoon of glue in another cup (some directions call for 1 teaspoon of water to be added also). Students should record their observations of the two liquids in their science notebooks.
3. While stirring with a craft stick, slowly add Borax solution until a thick glob forms. This will take just a small amount of solution.
4. Remove the glob from the cup and knead it. Excess solution may be removed with a paper towel.
5. Students should stretch and manipulate the polymer, then record their observations in their science notebooks, noting how the properties have changed.
6. Compare the two polymers. How are they alike or different?
When all of the students have finished the experiment, discuss their observations as a class.
Teaching Notes and Tips
Students should wear safety goggles during this experiment.
Be careful not to get it on clothing or carpet.
If time is limited, the cups of Borax solution and liquid laundry starch could be prepared ahead of time by the teacher. You may want to double the amounts of glue and solutions used in the experiment to provide a larger sample for students to work with.
Polymer One has the consistency of Silly Putty and the students love to play with it. I have often had students make a lump of their own putty. Each student is given about 20ml of liquid laundry starch in a cup and adds glue until a glob of putty forms. I have found that the measurements don't need to be exact. If someone adds too much glue, we just add a little more starch. We sometimes remove the excess starch from the putty by rinsing under cold water, but be sure none of the polymer goes down the drain. It may be colored using markers. Using the blue gel school glue creates a more rubbery polymer. Putty should be stored in an airtight container or bag. I always forewarn my students that it is quite possible someone's putty won't form and will remain a gluey mass, even though everything was done according to instructions.
I have not tried this activity in this format but feel confident of its success. The experiment is more controlled, and comparing the two polymers will provide a more comprehensive experience for the students.
5.I.B.1.1- perform a controlled experiment