Students explore Hooke's law while working in small groups at their lab benches. They collect displacement data for springs with unknown spring constants, k, by adding various masses of known weight. After exploring Hooke's law and answering a series of application questions, students apply their new understanding to explore a tissue of known surface area. Students then use the necessary relationships to depict a cancerous tumor amidst normal tissue by creating a graph in Microsoft Excel.

Students explore the properties of composites using inexpensive materials and processing techniques. They create beams using Laffy Taffy and water, and a choice of various reinforcements (pasta, rice, candies) and fabricating temperatures. Student groups compete for the highest strength beam. They measure flexure strength with three-point bend tests and calculations. Results are compared and discussed to learn how different materials and reinforcement shapes affect material properties and performance.

Students learn about stress and strain by designing and building beams using polymer clay. They compete to find the best beam strength to beam weight ratio, and learn about the trade-offs engineers make when designing a structure.

In this math activity, students conduct a strength test using modeling clay, creating their own stress vs. strain graphs, which they compare to typical steel and concrete graphs. They learn the difference between brittle and ductile materials and how understanding the strength of materials, especially steel and concrete, is important for engineers who design bridges and structures.

Students create and analyze composite materials with the intent of using the materials to construct a structure with optimal strength and minimal density. The composite materials are made of puffed rice cereal, marshmallows and chocolate chips. Student teams vary the concentrations of the three components to create their composite materials. They determine the material density and test its compressive strength by placing weights on it and measuring how much the material compresses. Students graph stress vs. strain and determine Young's modulus to analyze the strength of their materials.

Students learn about viscoelastic material behavior, such as strain rate dependence and creep, by using silly putty, an easy-to-make polymer material. They learn how to make silly putty, observe its behavior with different strain rates, and then measure the creep time of different formulations of silly putty. By seeing the viscoelastic behavior of silly putty, students start to gain an understanding of how biological materials function. Students gain experience in data collection, graph interpretation, and comparison of material properties to elucidate material behavior. It is recommended that students perform Part 1of the activity first (making and playing with silly putty), then receive the content and concept information in the associated lesson, and then complete Part 2 of the activity (experimenting and making measurements with silly putty).

Students learn about nanocomposites, compression and strain as they design and program robots that compress materials. Student groups conduct experiments to determine how many LEGO MINDSTORMS(TM) NXT motor rotations it takes to compress soft nanocomposites, including mini marshmallows, Play-Doh®, bread and foam. They measure the length and width of their nanocomposite objects before and after compression to determine the change in length and width as a function of motor rotation.

Students are introduced to the unit challenge: To develop a painless means of identifying cancerous tumors. Solving the challenge depends on an understanding of the properties of stress and strain. After learning the challenge question, students generate ideas and consider the knowledge required to solve the challenge. Then they read an expert's opinion on ultrasound imaging and the potentials for detecting cancerous tumors. This interview helps to direct student research and learning towards finding a solution.

Following the steps of the iterative engineering design process, student teams use what they learned in the previous lessons and activity in this unit to research and choose materials for their model heart valves and test those materials to compare their properties to known properties of real heart valve tissues. Once testing is complete, they choose final materials and design and construct prototype valve models, then test them and evaluate their data. Based on their evaluations, students consider how they might redesign their models for improvement and then change some aspect of their models and retest aiming to design optimal heart valve models as solutions to the unit's overarching design challenge. They conclude by presenting for client review, in both verbal and written portfolio/report formats, summaries and descriptions of their final products with supporting data.

As part of the engineering design process to create testable model heart valves, students learn about the forces at play in the human body to open and close aortic valves. They learn about blood flow forces, elasticity, stress, strain, valve structure and tissue properties, and Young's modulus, including laminar and oscillatory flow, stress vs. strain relationship and how to calculate Young's modulus. They complete some practice problems that use the equations learned in the lesson mathematical functions that relate to the functioning of the human heart. With this understanding, students are ready for the associated activity, during which they research and test materials and incorporate the most suitable to design, build and test their own prototype model heart valves.

Students use the engineering design process to solve a real-world problem shoe engineering! Working in small teams, they design, build and test a pair of wearable platform or high-heeled shoes, taking into consideration the stress and strain forces that it will encounter from the shoe wearer. They conclude the activity with a "walk-off" to test the shoe designs and discuss the design process.

Students are presented with an engineering challenge that asks them to develop a material and model that can be used to test the properties of aortic valves without using real specimens. Developing material that is similar to human heart valves makes testing easier for biomedical engineers because they can test new devices or ideas on the model valve instead of real heart valves, which can be difficult to obtain for research. To meet the challenge, students are presented with a variety of background information, are asked to research the topic to learn more specific information pertaining to the challenge, and design and build a (prototype) product. After students test their products and make modifications as needed, they convey background and product information in the form of portfolios and presentations to the potential buyer.

Students are introduced to the multidisciplinary field of material science. Through a class demo and PowerPoint® presentation, they learn the basic classes of materials (metals, ceramics, polymers, composites) and how they differ from one another, considering concepts such as stress, strain, ductile, brittle, deformation and fracture. Practical examples help students understand how the materials are applied, and further information about specific research illustrates how materials and material science are useful in space exploration. A worksheet and quiz are provided.

After conducting the associated activity, students are introduced to the material behavior of elastic solids. Engineering stress and strain are defined and their importance in designing devices and systems is explained. How engineers measure, calculate and interpret properties of elastic materials is addressed. Students calculate stress, strain and modulus of elasticity, and learn about the typical engineering stress-strain diagram (graph) of an elastic material.

After a brief history of plastics, students look more closely as some examples from the abundant types of plastics found in our day-to-day lives. They are introduced to the mechanical properties of plastics, including their stress-strain relationships, which determine their suitability for different industrial and product applications. These physical properties enable plastics to be fabricated into a wide range of products. Students learn about the different roles that plastics play in our lives, Young's modulus, and the effects that plastics have on our environment. Then students act as industrial engineers, conducting tests to compare different plastics and performing a cost-benefit analysis to determine which are the most cost-effective for a given application, based on their costs and measured physical properties.

This lesson culminates the unit with the Go Public phase of the legacy cycle. In the associated activity, students depict a tumor amidst healthy body tissue using a Microsoft Excel® graph. In addition, students design a brochure for both patients and doctors advertising a new form of painless yet reliable breast cancer detection. Together, the in-class activity and the take-home assignment function as an assessment of what students have learned throughout the unit.

Students learn about the variety of materials used by engineers in the design and construction of modern bridges. They also find out about the material properties important to bridge construction and consider the advantages and disadvantages of steel and concrete as common bridge-building materials to handle compressive and tensile forces.

Students are introduced to Hooke's law as well as stress-strain relationships. First they learn the governing equations, then they work through several example problems, first individually, then as a class. Through the lesson's two-part associated activity, students 1) explore Hooke's law by experimentally determining an unknown spring constant, and then 2) apply what they've learned to create a strain graph depicting a tumor using Microsoft Excel®. After the activities, the lesson concludes with a stress-strain quiz to assess each student's comprehension of the concepts.

Students are introduced to the concepts of stress and strain with examples that illustrate the characteristics and importance of these forces in our everyday lives. They explore the factors that affect stress, why engineers need to know about it, and the ways engineers describe the strength of materials. In an associated literacy activity, while learning about the stages of group formation, group dynamics and team member roles, students discover how collective action can alleviate personal feelings of stress and tension.

Students are presented with a biomedical engineering challenge: Breast cancer is the second-leading cause of cancer-related death among women and the American Cancer Society says mammography is the best early-detection tool available. Despite this, many women choose not to have them; of all American women at or over age 40, only 54.9% have had a mammogram within the past year. One reason women skip annual mammograms is pain, with 90% reporting discomfort. Is there a way to detect the presence of tumors that is not as painful as mammography but more reliable and quantifiable than breast self-exams or clinical breast exams? This three lesson/three activity unit is designed for first-year accelerated or AP physics classes. It provide hands-on activities to teach the concepts of stress, strain and Hooke's law, which students apply to solve the challenge problem.