Stephanie Kwolek
Lesson OverviewStephanie Kwolek is the inventor of Kevlar, a polymer composite material. In this set of explorations, we are introduced to Stephanie through her DuPont commercial and a biography. Students explore a simple polymer and then are given several options to create different composites. The characteristics of these composites are tested for strength, durability, elasticity, and other parameters. Students are invited to select a composite they have engineered and then develop a technical guide and application for their product.
I. The STEM Story: The Stephanie Kwolek Story
There are three parts to the Stephaine Kwolek story, the video commercial, the scripted commercial, and the biography. While reading the story, keep track of anything that the learner finds interesting.
Allow students an opportunity to ask question or pose reactions about the story or presentation. It might be helpful to ask students if anything in the story interested them. What would they like to know more about. Collect ideas on the board. It is often helpful to have students take the role of a scientist, “What would a chemist find interesting in this story.” There are several social, historical, economic, political, and technological questions that we can generate from this story. Here we are primarily interested in those related to science.
One way to prompt this would be to ask questions such as:
"What do you find interesting about the story?"
"What would you like to know more about?"
Ideally, the learner should record observations or questions in a STEM notebook. See directions for STEM Notebook here.
II. Getting Started
Review Stephanie Kwolek's story and the development of Kevlar. She knew much about the polymer she was using and of various other chemicals. Her challenge was to combine these materials to create a composite. Kevlar is a composite, a combination of a polymer, like plastic, and some other material.
Suggest to the class that they be like Kwolek and create their own composite. They may need to know something about polymers and have some experience with the materials they would add as composites before they start, however.
Once we have generated a number of ideas and questions from the story, it important to categorize the questions into similar groupings. For example, here is a listing of possible areas of interests stimulated by the students and the teacher: Chemical, polymers, composites, Kwolek’s life, DuPont, social conditions of the 1950’s through 1980’s, Kevlar©, chemistry, textiles, etc. It becomes the teacher’s role to organize the questions and ideas into a summary statement for each group. Shaping some of the questions around Polymers, Chemicals, Composites, and Manufacturing allows the planned explorations to serve the needs of answering some of the questions.
III. Polymers. In this first set of explorations students test a simple polymer, gelatin.
A. Becoming Familiar with a Polymer
The first exploration gives students an opportunity to use a natural polymer, gelatin. We are familiar with its characteristics in products like Jello.
IV. Chemistry of Materials
Now that we have an understanding of a basic polymer, we can begin to think about how we can alter it. Adding various chemicals to the polymer can modify the nature of the polymer. How can we make a polymer more sticky? More hard? More stretchy? It is important to understand the nature of some chemical reactions so we can add these to modify the gelatin polymer.
B. White PowdersChemists and chemical engineers need to know the characteristics of different materials to both identify them and then to use them for various applications. This exploration gives students an opportunity to conduct tests to differentiate white powders from one another.
C. Chemical ReactionsWhen some chemical materials are mixed under certain environments, a chemical change can occur. Sometimes elements can be combined to for a molecule (synthesis), sometimes we can take a part a molecule and make elements (analysis), and sometimes we trade atoms or molecules (replacement).
D. Atomic Models How do chemists understand the nature of atoms and how molecules combine? In this exploration students combine different ratios of components to determine the ideal ratio to produce a gas. A fixed amount of Sodium Bicarbonate (Baking soda) is mixed with different amounts of Tartaric Acid (Creme of Tartar). By collecting gas from the reaction, a model can be assembled to describe the nature of the molecule.
E. Enhancing and testing a Natural Polymer We can enhance gelatin as a polymer by encouraging the molecules to link up using a polymerizing agent. In this exploration students add borax to the gelatin mixtures in various proportions to demonstrate the action of polymerization.
To describe any material and its characteristics, a standard must be measured. For example, how sticky a substance is is a matter of interpretation unless we have a specific test that gives a quantifiable result. In this exploration students test gelatin strips for stretch, memory, and stickiness.
V. STEM Challenge: Designing a Composite.
Now that we know something of polymers like gelatin and casein, and we have some background in the nature of materials like alum, baking soda, creme of tartar, borax, and other materials,we can now invent a composite material. What would happen if we mixed a polymer with a material? What kind of composite could we make? How can we think like Stephanie Kwolek and design a composite to solve a problem?
IV. Examining the Characteristics of other Polymers. We spent sometime messing around with a natural polymer, gelatin. It is a good material to experiment on as it is a non toxic food stuff. There are a great deal of other polymers that we can explore as well. Casein is a milk protein that can be made into a glue or plastic. White glue can be transformed into silly putty. Polyvinyl alcohol is another relatively harmless polymer.
