Materials Included In Kit

Additional Materials Required

Prelab Preparation

In the Prelab Activity, present to students the current recipe for Gluep. Demonstrate to the class the current mixture by making a sample of Gluep. If desired, you can decrease the amounts of the ingredients proportionally. Show students that the current substance has very little bounce. Follow the current recipe: 

Current Gluep Recipe: In one container, dissolve 10 g of white glue in 10 g of water. In a second container, dissolve 10 g of sodium borate in 10 g of water. Mix the two solutions together by adding the glue mixture to the sodium borate mixture. This is called the 10-10-10-10 formula. This current recipe for making Gluep results in a runny, milky, slime-like substance. The buyer wants a bouncy substance; this recipe does not satisfy the customer’s requirement for “bounciness.”

Safety Precautions

Sodium borate is slightly toxic by inhalation and ingestion. Some people are allergic to dry, powdered sodium borate. Use adequate ventilation when performing this lab. When not in use, set the Gluep polymer in a paper cup; the Gluep polymer may leave stains on wood, upholstery or carpet. Do not allow students to take the Gluep home as it may be toxic by ingestion. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. Gluep may be disposed of in the solid waste disposal according to Flinn Suggested Disposal Method #26a.

Teacher Tips

• Enough materials are provided in this kit for 30 students working in pairs or for 15 teams of students.
• Two Gluep Money reproducible master sheets are provided (Teacher PDF). If you choose to use money in your classroom, copy one of each sheet for each student research team. This totals $8.00, the proposed student budget. Copy extra money for your use as the “bank.” Allow more or less money for students as you see necessary; however, an $8.00 budget has worked well in classroom testing of this lab. Consider copying the money on colored cardstock.
• Spend one class period on the Prelab Activity and the following class period on the actual research. This gives you 24 hours to fill orders. The glue, however, must be dispensed right before class. Students must purchase the cups for dispensing the sodium borate and glue.
• Students will be tempted to use a trial and error method, rather than a systematic procedure. Stress that manufacturers do not have this luxury due to economics and time.
• Students can test the Gluep samples by placing the sample on the edge of a counter and pushing off gently. Mark the height of the first bounce on a piece of paper taped to the cabinet underneath and measure the bounce height with a ruler. Bounce height is fairly difficult to measure, and values obtained are dependent on many factors—shape of ball, size of ball, how long the ball sat before testing, etc. It is recommended that three trials be measured for each ball and an average value obtained. The research team that wins the “contract” is the group who spent the least amount of money and is in the top three of the bounce-off contest.
• The size of the Gluep sample does have an effect on the bounce. The smaller-size Gluep balls bounce higher than larger ones. You may want to specify the weight of sample to be submitted, or create an extension activity based on size.
• Emphasize to students that they must estimate carefully what they need to order. Some groups will want to purchase items on a “when I discover I need it” basis. This is not necessarily how the real world works. To encourage careful planning, tell students that it will cost them twice as much if they have to come back for more. And NO, they cannot return unused items for a refund.
• At the conclusion of the lab, have each group bring up their most bouncy sample and have a “Bounce-Off.” Ties are broken by the team who spent the least amount of money. Consider giving an official contract, and prizes to the winning team.
• This is an open-ended lab. Allow students to experiment with different recipes and make conclusions. However, ingredients are limited to those provided—no other ingredients are allowed. The data provided below may vary greatly, so use the data as a very rough guideline.

Sample Data

*Note: The best bounce occurred in our testing with 10 g of glue mixed with 2.5 g of sodium borate in 5 g of water. Actual results may vary.

Answers to Questions

1. What ingredient in the Gluep recipe appears to be responsible for bounce? Explain.

   It appears that more glue and less sodium borate (lower amount of cross-linking) and less water make the Gluep bouncier.

2. How did placing a cost on lab materials change your approach to the problem presented? How do you think this affects chemical industries in real life?

   More careful planning was necessary. Chemical industries must be limited to how much experimentation they can do because the research must produce a profit.

Teacher Handouts

11901_Teacher1.pdf

References

Special thanks to Laura Spencer, Edmonds-Woodway High School, Edmonds, WA, for providing the idea and instructions for this activity. The concept for Laura’s lesson was developed in conjunction with Marilynn Opper during the 1996 Dow/NSTA Summer Workshop.

Introduction

The Gluep Production Lab is a real-life, open-ended, discovery lab activity with an element of corporate competition. Student research teams are challenged to use the scientific method to improve the polymer recipe and make a bouncier Gluep—all while staying on the company budget. Students design and conduct their own mini-research project as they try to win the contract to manufacture Gluep. Students will also learn about polymers and have fun at the same time!

Concepts

• Polymers
• Chemical manufacturing
• Scientific method

Background

The Gluep polymer is a fluid in that it has some properties of a liquid such as flowing and dripping and also properties of a solid such as bouncing and shattering. By altering the ratio of ingredients in the recipe, the properties of the polymer (i.e., more flow or more bounce), can be altered.

Polymers are made by combining many individual units called monomers into a single larger molecule. The monomer in Gluep is polyvinyl acetate (from the white glue) shown in Figure 1.

Sodium borate, Na₂B₄O₇, dissolves in water to form borate ions, B(OH)₄^– (Equation 1), which then form bridges between the polyvinyl acetate chains. This creates a cross-linked polymer. The cross-linking and natural hydrogen bonding create a three-dimensional polymer with open spaces for water to occupy.

Materials

Prelab Questions

The research director (teacher) will conduct a background session for all scientists. In this presentation, the research director will show how the Gluep ball is currently being produced and lay out some of the problems with the current recipe.

Current Gluep Recipe

1. In one container, dissolve 10 g of white glue in 10 g of water.
2. In a second container, dissolve 10 g of sodium borate in 10 g of water.
3. Mix the two solutions together by adding the glue mixture to the sodium borate mixture. This is called the 10-10-10-10 formula.

This current recipe for making Gluep results in a runny, milky, slime-like substance. The buyer wants a bouncy substance; this recipe does not satisfy the customer’s requirement for “bounciness.”

It is the task of your team to systematically test different formulas of Gluep to determine which ingredient is responsible for the “bounce factor” of Gluep—glue, sodium borate or water. Your team will, however, be limited by your company’s budget and be competing against other research teams to improve the Gluep formula at the lowest cost possible.

Your team is to design a laboratory procedure which will answer the following questions

1. What ingredient is responsible for the bounce?
2. What is the optimum recipe for bouncy Gluep?

Each team has been authorized a maximum budget of $8.00, and must complete the research in one class period, so consider this in your procedure design. Fines will be assessed on research teams for improper use of time and failure to properly clean up a lab station. If a team runs out of money or is fined and has no money to pay the fine, a loan may be obtained from the research director in exchange for a grade adjustment on the project, as determined by the research director.

Safety Precautions

Sodium borate is slightly toxic by inhalation and ingestion. Some people are allergic to dry, powdered sodium borate. Use adequate ventilation when performing this lab. When not in use, set the Gluep polymer in a paper cup; the Gluep polymer may leave stains on wood, upholstery, or carpet. Wear chemical splash goggles, chemical-resistant gloves, and a chemical-resistant apron. Wash hands thoroughly with soap and water before leaving the laboratory.

Procedure

Day 1

1. Write a research plan (laboratory procedure) for researching the “bounciness” of Gluep. Your team may wish to use a flow chart. Use the current recipe as the control and compare the bounciness of the new recipe to the control recipe. Remember to change only one factor at a time. A sample flow chart is shown below
   {11901_Procedure_Figure_1}
2. Fill in a Gluep Materials Order Form and determine the cost of your research. (Note: Ample supplies for all parts of your research should be ordered at this time. Try to plan ahead and estimate carefully what will be needed. Additional supplies may be ordered later, but at a penalty of twice the cost.)
3. Submit your research plan and order form to your instructor.

Day 2

4. Construct a data table. Conduct your research and record data in a data table. Analyze the data.
5. Submit your bounciest Gluep sample to the research director for comparison. The research team who developed the best product and spent the least amount of money to perform the research (and saved the company the most money) will win the contract. No money will be refunded for unused materials.
6. Gluep may be disposed of in the solid waste disposal. Consult your instructor for additional appropriate disposal procedures.

Student Worksheet PDF

11901_Student1.pdf