Teacher Notes

Chemistry of Sports—Golf Ball Design

Student Laboratory Kit

Materials Included In Kit

Glue, white, 800 mL
Paper cups, 8 oz., 75
Sodium borate, Na2B4O7•10H2O, 900 g
Wood sticks, for stirring, 75

Additional Materials Required

Balance
Graduated cylinder, 10 mL
Ruler
Water, tap

Prelab Preparation

In the prelab activity, you may elect to show students a sample of the golf ball polymer formed by using the following proportion of reactants and procedure: 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 results in a runny, milky, slime-like substance.

Point out that such as substance will clearly not work for the core of a golf ball and challenge students to optimize the reaction composition to produce a bouncier “golf ball.” Alternatively, you may choose to have students determine independently that the 10-10-10-10 formula is not ideal for golf-ball production.

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 polymer in a paper cup; the 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.

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. The polymer product 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 24 students working in groups of 3 pairs or for 8 teams of students.
  • Students will be tempted to use a trial and error method, rather than a systematic procedure. Stress that golf ball manufacturers do not have this luxury due to economics and time.
  • The size of the polymer sample does have an effect on the bounce. The smaller-sized polymer 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.
  • 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.

Correlation to Next Generation Science Standards (NGSS)†

Science & Engineering Practices

Asking questions and defining problems
Planning and carrying out investigations
Analyzing and interpreting data
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluation, and communicating information

Disciplinary Core Ideas

MS-ETS1.A: Defining and Delimiting Engineering Problems
MS-ETS1.C: Optimizing the Design Solution
MS-PS1.A: Structure and Properties of Matter
HS-ETS1.B: Developing Possible Solutions

Crosscutting Concepts

Structure and function
Scale, proportion, and quantity

Performance Expectations

MS-PS1-3. Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.
MS-ETS1-1. Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
MS-ETS1-3. Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.

Sample Data

{14110_Data_Table_1}

*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. Which composition, or proportion of reactants, results in the “golf ball” that bounces highest?

    It appears that more glue and less sodium borate (lower amount of cross-linking) and less water make the bounciest “golf ball.”

  2. Provide a chemical explanation as to why you think this composition is able to produce the highest bouncing golf ball.

    Borate ions serve as cross-linking agents that tether the layers of polyvinyl acetate together into a polymer network. Water molecules occupy empty spaces in the network. It is likely that as the amount of borate ions increases in the network, the number of tethers increases. If enough sodium borate is added the number of tethers between layers of polyvinyl acetate increases to the point that the polymer network becomes rigid, or inflexible, and does not bounce optimally. The ideal ratio between cross-linking sodium borate and polymeric polyvinyl acetate is approximately 1:4 based on mass, as determined by iterative experimentation.

Recommended Products

Item No. Description
AP8499 Golf Ball Design—Chemistry of Sports—Student Laboratory Kit

Student Pages

Chemistry of Sports—Golf Ball Design

Introduction

The relationship between science and sports is undeniable. Tennis racquets and bicycles are made lighter and stronger by nanotechnology, footballs are inflated to the appropriate pressure (we hope) in accordance with the ideal and simple gas laws, sports drinks are carefully made and studied using analytical chemistry to improve athletic performance, and breathable and comfortable apparel is designed by applying the principles of materials chemistry, to name a few of the connections. In this lab, you will design the best inner core of a golf ball possible by varying the composition of a reaction mixture to take advantage of the principles of polymer chemistry.

Concepts

  • Materials chemistry
  • Experimental design
  • Chemical reactions
  • Polymer chemistry
  • Chemical and physical changes
  • STEM design

Background

Nearly anyone with even a remote interest in the game of golf is likely to recognize the name Tiger Woods. His name has become almost synonymous with golf. In contrast, most people don’t know that polymers are just as intimately linked with the sport. Golf balls rely on polymer chemistry to give them the ability to withstand the significant mechanical force imposed by the swing of a golf club, repeatedly without breaking.

Approximately 80% of commercial golf balls are made of a “soft” polymer core meant to efficiently absorb and convert the energy in a golf swing to kinetic energy (and result in long drives) surrounded by a “hard” polymer cover meant to withstand repeated force without cracking (i.e., to be durable). Polymers are essentially very long springs that when struck coil and uncoil, acting as molecular springs to absorb the energy in a golf swing in the most elastic way possible to ensure optimal energy transfer from the swing to the ball.

Polymers are made by combining many individual units called monomers into a single larger molecule. The monomer is polyvinyl acetate (from white glue) is shown in Figure 1. It can be mixed with sodium borate, Na2B4O7, to form a springy polymer.

{14110_Background_Figure_1_Polyvinyl acetate}
Sodium borate dissolves in water to form borate ions, B(OH)4– (Equation 1), which then form bridges between the polyvinyl acetate chains.
{14110_Background_Equation_1_Dissolving of sodium borate}
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.

This experiment will focus on the softer core of the golf ball and challenge you to design a golf ball that can travel the furthest, as determined by the distance it travels when bounced from a tabletop onto the floor.

Materials

Glue, white, 100 mL
Sodium borate, Na2B4O7•10H2O, 150 g
Water, tap, 50 mL
Balance
Graduated cylinder
Paper cups, 8 oz., 5 or less
Ruler
Wood sticks, 5 or less, for stirring

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 polymer in a paper cup; the 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

  1. Synthesize a poorly bouncing golf ball as a baseline according to the following procedure:
    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.
  2. Obtain enough raw material to design approximately 5–10 golf balls (depending on the size): 100 g sodium borate and 100 mL white glue.
  3. Write a laboratory procedure for designing a high-bouncing golf ball. Use the 10-10-10-10 reaction composition as the control.
  4. Test the “golf balls” by placing samples on the edge of a table and pushing off gently. Mark the height of the first bounce on a piece of paper taped to a cabinet or table leg, 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. Control for as many factors as possible to ensure test protocols are consistent from one ball to the next. Post-Lab Questions 1. Which composition, or proportion of reactants, results in the “golf ball” that bounces highest? 2. Provide a chemical explanation as to why you think this composition is able to produce the highest bouncing golf ball.
Post-Lab Questions
  1. Which composition, or proportion of reactants, results in the “golf ball” that bounces highest?
  2. Provide a chemical explanation as to why you think this composition is able to produce the highest bouncing golf ball.

†Next Generation Science Standards and NGSS are registered trademarks of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.