Rocks cover the earth's surface, including what is below or near human-made structures. With rocks everywhere, breaking rocks can be hazardous and potentially disastrous to people. Students are introduced to three types of material stress related to rocks: compressional, torsional and shear. They learn about rock types (sedimentary, igneous and metamorphic), and about the occurrence of stresses and weathering in nature, including physical, chemical and biological weathering.

To experience the three types of material stress related to rocks — tensional, compressional and shear — students break bars of soap using only their hands. They apply force created by the muscles in their own hands to put pressure on the soap, a model for the larger scale, real-world phenomena that forms, shapes and moves the rocks of our planet. They also learn the real-life implications of understanding stress in rocks, both for predicting natural hazards and building safe structures.

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 explore the physical and psychological effect of stress and tension on human beings. Concepts of stress and stress management are introduced. Students discover how perception serves to fuel a huge industry dedicated to minimizing risk and relieving stress. Students complete a writing activity focused on developing critical thinking skills. Note: The literacy activities for the Mechanics unit are based on physical themes that have broad application to our experience in the world concepts of rhythm, balance, spin, gravity, levity, inertia, momentum, friction, stress and tension.

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.

In this activity, students learn about creating a design directly from a CAD (computer-aided design) program. They will design a tower in CAD and manufacture the parts with a laser cutter. A competition determines the tower design with the best strength:weight ratio. Students also investigate basic structural truss concepts and stress concentrations. Partnership with a local college or manufacturing center is necessary for the completion of this project.

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.

Students are introduced to the similarities and differences in the behaviors of elastic solids and viscous fluids. Several types of fluid behaviors are described Bingham plastic, Newtonian, shear thinning and shear thickening along with their respective shear stress vs. rate of shearing strain diagrams. In addition, fluid material properties such as viscosity are introduced, along with the methods that engineers use to determine those physical properties.

In addition to the associated lesson, this activity functions as a summative assessment for the Using Stress and Strain to Detect Cancer unit. In this activity, students will create a 1-D strain plot in Microsoft Excel depicting the location of a breast tumor amidst healthy tissue. The results of this activity will function as proof of the accuracy and reliability of the students' breast cancer detection design.