Exploring materials

This exercise is a part of Educator Guide: Featured Activities / View Guide

Purpose: Students discover and evaluate information about how the structure and properties of matter relate to how the material is used, and how new materials transform society.

Procedural overview: After reading the Science News article “Materials that made us,” students will discuss why and how new materials are developed. Then students will work in groups to choose a material and research the material’s history, structure and function, along with any social, cultural, health or environmental issues related to its manufacture, use or disposal. Finally, student groups will develop museum-style exhibits to communicate what they learned to the class and answer questions about the findings.

Approximate class time: 1 or 2 class periods

Supplies:

Paper

Pencils

Exploring Materials student worksheet 

Computer with access to the internet, Science News and Science News for Students article archive

Poster board and other poster-making materials

Interactive meeting and screen-sharing application for virtual learning (optional)

Audio or video capture hardware and editing software (optional)

Want to make it a virtual lesson?

This activity can be done virtually by using interactive meeting software for group discussions and video-sharing technologies to record and deliver poster presentations. Student groups should use screen-sharing and file-sharing applications in which documents can be viewed and edited in real time.

Background information

Brief students about the interdisciplinary field of materials science as appropriate. Materials science focuses on understanding and applying the properties of matter to develop new materials, often for specific uses. The field combines chemistry, physics and engineering. Materials scientists might draw from observations and investigations in metallurgy, mineralogy, ceramics, polymers, nanotechnology, biology and other fields to create new materials.

Materials scientists might investigate mechanical properties, such as strength or elasticity; chemical properties, such as flammability or response to acids; electric properties, such as whether and how well the material conducts electric current; thermal properties, such as heat resistance or conductivity; optical properties, such as whether a material transmits, bends or blocks different wavelengths of light, and magnetic properties.

Directions for teachers:

The setup

For homework before the class, have students read the online Science News article “Materials that made us” and answer the guiding questions that follow, including writing an article summary.

If students need help summarizing, have them follow instructions in the Science News in High Schools resource “How to write a summary.”

Note that the article is longer than a typical news article. Reading and summarizing the article using the questions below could take an hour or more. Consider giving students the assignment a couple of days before you begin the classroom portion of the work or having students complete the reading and questions during a class period.

Guiding questions

1. What is the article’s main point?

Sample answer: People’s ability to study matter and synthesize new substances increased dramatically in the 20th and 21st centuries. Many of the materials we encounter or use every day have been made by humans through the intentional manipulation, recombination and reimagination of natural and human-made substances.

2. What three categories of human activity does the author focus on to support the main point?

Sample answer: The author explores the use of engineered materials in transportation (how we move), communication (how we connect) and applications of plastics (how plastics boomed).

3. What materials are identified in the article as transforming human activity in one or more of the three categories? Identify at least one material for each of the three categories.

Sample answer: The author describes several substances that are common in modern life that were developed in the past century. For transportation, the author highlights high-octane fuels for aircraft, lightweight alloys and composites (such as Avcoat and Nextel) and adhesives. For communication, the author highlights magnets, silicon transistors, optical glass fibers and nonstick polymers (Teflon). For plastics, the author highlights celluloid, Bakelite, plastic foam (Styrofoam), nylon, polypropylene and high-density polyethylene.

4. Summarize the section “Can we clean up?” in one paragraph.

Sample answer: Although many modern materials were developed to solve problems, many of these solutions have caused new problems. Many materials have had unanticipated environmental consequences, and a lot are not recycled or reused. Their use and disposal can cause pollution and contaminate air, soil and water, which contributes to problems such as declines in biodiversity, climate change and human illnesses. Materials scientists are developing new materials to solve the original problems hopefully without the same drawbacks.

5. Write a three-paragraph summary of the article’s main points.

Sample answer: People’s ability to study matter and synthesize new substances increased dramatically in the 20th and 21st centuries. Many of the materials we encounter or use every day have been made by humans through the intentional manipulation, recombination and reimagination of natural substances. The article explores the use of engineered materials in transportation (how we move), communication (how we connect) and applications of plastics (how plastics boomed).

The author describes several substances that are common in modern life that were developed in the past century. For transportation, the author highlights high-octane fuels for aircraft, lightweight alloys and composites (such as Avcoat and Nextel) and adhesives. For communication, the author highlights magnets, silicon transistors, optical glass fibers and nonstick polymers (Teflon). For plastics, the author highlights celluloid, Bakelite, plastic foam (Styrofoam), nylon, polypropylene and high-density polyethylene.

Although many modern materials were developed to solve problems, many of these solutions have caused new problems. Many materials have had unanticipated environmental consequences, and a lot are not recycled or reused. Their use and disposal can cause pollution and contaminate air, soil and water, which contributes to problems such as declines in biodiversity, climate change and human illnesses. Materials scientists are developing new materials to solve the original problems hopefully without the same drawbacks.

Class discussion

Before beginning the class discussion about “Materials that made us,” make sure students understand that two main goals of materials science and engineering are to develop new materials that solve a specific problem and to develop new uses and applications for existing materials.

Ask students to define the term “material.” Their answers may vary a great deal. Remind them that the term has a specific meaning in the context of this discussion. For this discussion, a substance is a form of matter. A material is a substance that has properties, sometimes modified or enhanced, that are desirable for some intended use.

Use the class discussion prompts below to prepare students to conduct the group research. Students should be encouraged to take notes for use later in the activity.

Have students answer the following questions during the discussion.

1. The article defines “materials”as “substances having properties which make them useful in machines, structures, devices and products.” List five examples of materials given in the article. Try to name the material itself and not the machine, device or product that includes the material.

Answers will vary. Students should identify five materials described by the article, such as high-octane fuels, aluminum alloys, glass-plastic composites, adhesives, rare-Earth magnets, silicon, optical glass fibers, nonstick polymers and various plastics, including celluloid, Bakelite, plastic foam (Styrofoam), nylon, polypropylene and high-density polyethylene.

2. How is the science of materials cross-curricular? Explain how each of the following scientific disciplines contributes to materials science: physics, chemistry, biology, environmental science and medicine.

Sample answer: Physics contributes understanding of a substance’s mechanical properties, such as strength or elasticity; electric properties, such as whether and how well the material conducts electric current; thermal properties, such as heat resistance or conductivity; optical properties, such as whether a material transmits, bends or blocks different wavelengths of light; and magnetic properties. Chemistry contributes to the understanding of chemical properties, such as flammability or response to acids; electric properties, such as whether and how well the material conducts electric current; magnetic properties; chemical composition and atomic or molecular structures of materials — as well as how different materials might react or otherwise interact with one another. Biology contributes information about organic substances and structures, how they are made or used by living things and how they affect living cells or tissues. Environmental science provides context for how different substances and materials interact with living and nonliving components and systems on Earth, and how they might break down or be absorbed in the environment. Medicine contributes an understanding of how different substances, materials, machines or devices affect the structure and function of human cells, tissues and organs and how materials, machines and devices can be used to heal, cure or treat injuries and illnesses and improve health and life.

3. The author concludes the article by looking forward to materials advances that might occur in the future. Which of those possible advances is most interesting to you? Why?

Answers will vary. Students should choose one of the materials described in the “Looking forward” slider at the end of the article. Students may need to click the link to the referenced article to learn more about a material. Sample answer: I am most interested in ultrasmooth polyamide films or membranes that can be used to desalinate ocean water. I know that as climate changes, access to freshwater will become an even greater global problem, and I think this material could help people have access to the water they need.

Research

Organize students into small groups. As a group, students will use internet resources or other resources to research engineered materials and their properties. Encourage students to use only sources that they believe to be reliable and to cite those sources in their research and presentation. The Science News in High Schools Just the Facts Educator Guide is designed to help students think critically about the trustworthiness of resources.  

Each group should answer the following questions.

1. Look around you and find or brainstorm an engineered material that interests you. Think about building materials, transportation, the health and beauty industry, the food and beverage industry, agriculture, the medical and pharmaceutical industry, science and exploration, aviation and space flight, environmental protection and remediation, technology or another field. What material will you research?

Sample answer: We will research carbon fiber, also called graphite fiber.

2. What can you find out about the material’s composition and structure? What element(s) is the material made of and how are the atoms or molecules arranged?

Sample answer: Carbon fiber is a polymer composed of carbon atoms bonded together in crystals aligned to form long, thin chains.

3. What about the material’s composition makes it useful?

Sample answer: This arrangement of crystals makes thin, lightweight and strong threads or fibers. The carbon fibers have a high strength-to-volume ratio, which makes twisted or braided carbon fiber material stronger than steel but much lighter. In addition, carbon fiber is stiff, has high tensile strength, is resistant to damage by chemicals, is heat tolerant and doesn’t expand or contract much when temperature changes. Materials made with carbon fiber materials are lightweight, strong and resistant to damage by heat or chemicals.

4. Pick a specific machine, device or product that contains the chosen material. What is the machine, device or product used for? List the materials in it.

Sample answer: Prosthetic running blades, also called running feet, are made of carbon fiber–reinforced polymer composites. These devices allow people who have lost their lower limbs to run. They fit on the leg and contain connectors made of various carbon fiber composites, lightweight metal alloys and plastics.

5. How does your chosen material help make the machine, device or product useful?

Sample answer: The flexibility and strength of the carbon fibers allow elastic energy to be stored when a person’s weight is placed on the blade. When the weight is lifted off the blade, the carbon fibers return to their original shape, releasing the stored energy like a spring, which aids in stepping forward and swinging the leg.

6. Why was the material you selected developed, and how has it evolved over time?

Sample answer: The first carbon fibers were made in the second half of the 1800s for use as a lightbulb filament. The material needed to glow as electric current flowed through it but not immediately burn up. Cotton threads and bamboo slivers baked at high temperatures were transformed into an all-carbon filament. By the end of the 1950s, low-strength carbon fibers were being used for other purposes, but it wasn’t until the early 1960s that researchers developed a part-chemical, part-mechanical process to manufacture high-strength carbon fibers by stretching or spinning rayon to form long strands of fibers and heating them to extreme temperatures. This process causes the atoms inside the fibers to vibrate and expel most of the atoms of elements other than carbon.

7. Does the material have any unexpected or surprising properties or uses?

Sample answer: Carbon fiber is easy to work with because it is strong, rigid and lightweight. Carbon fiber is traditionally used in aerospace applications, for automobiles, military applications and sporting goods. Carbon fibers are now also being used in the medical field as a component in X-ray and imaging equipment because X-rays pass through carbon fibers. This property of carbon fibers means they do not block or distort images of structures on X-rays and other medical images.

8. Does the material pose any problems to society, culture, human health or the environment?

Sample answer: Yes. Manufacturing carbon fiber requires a lot of energy, so it contributes to pollution and climate change. Carbon fibers can break or shatter, so carbon-fiber products cannot be repaired and must be discarded and replaced if damaged. Carbon fiber doesn’t rust, corrode or degrade with time or repeated stress, so it lasts a long time in landfills and in the oceans. Recycling carbon fiber is expensive and difficult because carbon fibers are woven together in specific patterns depending on the purpose of the item, so the material would have to be unraveled and rebuilt to form a new item.

9. Have there been any innovations to address the problems caused by the material?

Sample answer: New processes to reclaim and recycle carbon fiber have been developed, including pyrolysis, milling and shredding. Also, because carbon fiber doesn’t rust, corrode, degrade or fatigue like metals do, scientists and engineers have developed new uses for carbon fibers to replace metals and plastics and take advantage of the long life cycle of carbon fibers.

Presentation

To present their findings, each group will create a museum-style exhibit about the material they chose and the machines, devices or products that use the material. Students should create a poster and include a picture or video of the material they researched. They might also bring in a sample of the material or a product or device that includes it. The creation of the exhibit could be done at home or during a second class period.

After student groups have constructed their exhibits, the class should walk through the “museum,” explore the different exhibits and answer the following questions. This part of the activity also could be done as a class discussion.

1. How have technological advances driven the production of new materials?

Sample answer: New technologies, such as electron microscopes and X-ray crystallography, have enabled scientists to study how matter and its behavior in new ways with more detail. These tools have enabled engineers to design materials and test different iterations to develop materials that are ideally suited to the intended purpose. With the introduction of new devices and products, the public desire for smaller, faster, lighter and better versions drive further developments.

2. What patterns do you observe between why materials are conceived and developed and the impacts and policies that follow that development?

Sample answer: A lot of materials are developed to make machines, devices and products smaller, faster, lighter, more efficient, less expensive and more convenient. While some consequences can be predicted, often the consequences of a material’s manufacture, use and disposal aren’t fully understood until the material has been created and widely used. As a result, new materials sometimes have negative effects on human health and the environment, and new policies regarding their manufacture, use and disposal must be developed to mitigate the impacts. Some companies practice “cradle-to-grave” engineering and design to address these issues. These companies consider and model the environmental impacts of each stage of the material’s life cycle as the material is developed and deployed.

3. What patterns do you observe in who develops new materials?

Sample answer: In the past, “basic curiosity and serendipity” led to new materials. Today, a lot of materials are developed by scientists trying to meet a specific engineering need or solve a particular problem. New materials are developed by government or military research scientists, scientists working for chemical or consumer-product corporations and university research scientists.

4. What similarities can you identify in the composition and structure of different materials and how they are used (or the functionality they provide to a device or product)?

Answers will vary depending on the materials presented in the exhibits. Sample answer: I noticed that metallic substances, such as alloys, are commonly developed to increase the strength and durability or to enhance the electric and magnetic properties of a machine, device or product. Lightweight materials are commonly made from nonmetallic substances and are engineered to be less dense.

Additional resources

Science News articles:

C. Wilke. “A diamondlike structure gives some starfish skeletons their strength.” Science News. Published online February 10, 2022.

M. Temming. “These colorful butterflies were created using transparent ink.” Science News. Published online September 28, 2021.

E. Conover. “Morphing noodles start flat but bend into curly pasta shapes as they’re cooked.” Science News. Published online May 11, 2021.

I. Amato. “Making the Right Stuff.” Science News. Published August 12, 1989.

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