Students learn about the role engineers play in designing and building truss structures. Simulating a real-world civil engineering challenge, student teams are tasked to create strong and unique truss structures for a local bridge. They design to address project constraints, including the requirement to incorporate three different polygon shapes, and follow the steps of the engineering design process. They use hot glue and Popsicle sticks to create their small-size bridge prototypes. After compressive load tests, they evaluate their results and redesign for improvement. They collect, graph and analyze before/after measurements of interior angles to investigate shape deformation. A PowerPoint® presentation, design worksheet and data collection sheet are provided. This activity is the final step in a series on polygons and trusses.

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.

Students learn about STEM education through an engineering design challenge that focuses on improving building materials used in shantytowns. First, they consider the factors that lead to shantytown development. After researching the implications of living in shantytowns, students design, build and test cement-based concrete block composites made of discarded and/or recycled materials. The aim is to make a material that is resistant to degradation by chemicals or climate, can withstand natural disasters, and endure through human-made conditions (such as urban overcrowding or pollution). The composites must be made of materials that are inexpensive and readily available so that they are viable alternative in shantytown communities. Students assess the results both chemically and physically and then iterate their designs with the materials that proved to be strongest.

Students learn why shock absorbers are necessary on vehicles, how they dampen the action of springs, and what factors determine the amount of dampening. They conduct an experiment to determine the effect of spring strength and port diameter on the effectiveness of a shock absorber. Using a syringe, a set of springs, and liquids of different viscosities, students determine the effects of changing pressures and liquids on the action of a model shock absorber. They analyze their data through the lens of an engineer.

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.

Through hands-on group projects, students learn about the force of compression and how it acts on structural components. Using everyday materials, such as paper, toothpicks and tape, they construct structures designed to (hopefully) support the weight of a cinder block for 30 seconds.

Working as engineering teams, students design and create model beam bridges using plastic drinking straws and tape as their construction materials. Their goal is to build the strongest bridge with a truss pattern of their own design, while meeting the design criteria and constraints. They experiment with different geometric shapes and determine how shapes affect the strength of materials. Let the competition begin!

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.

To introduce the two types of stress that materials undergo compression and tension students examine compressive and tensile forces and learn about bridges and skyscrapers. They construct their own building structure using marshmallows and spaghetti to see which structure can hold the most weight. In an associated literacy activity, students explore the psychological concepts of stress and stress management, and complete a writing activity.

Students conduct several simple lab activities to learn about the five fundamental load types that can act on structures: tension, compression, shear, bending, and torsion. To learn the telltale marks of failure caused by these load types, they break foam insulation blocks by applying these five load types, carefully examine each type of fracture pattern (break in the material) and make drawings of the fracture patterns.

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 work within constraints to construct model trusses and then test them to failure as a way to evaluate the relative strength of different truss configurations and construction styles. Each student group uses Popsicle sticks and hot glue to build a different truss configuration from a provided diagram of truss styles. Within each group, each student builds two exact copies of the team's truss configuration using his/her own construction method, one of which is tested under shear conditions and the other tested under compression conditions. Results are compiled and reviewed as a class to analyze the strength of different types of shapes and construction methods under the two types of loads. Students make and review predictions, and normalize strengths. Teams give brief presentations to recap their decisions, results and analysis.

Students learn about the types of waves and how they change direction, as well as basic wave properties such as wavelength, frequency, amplitude and speed. During the presentation of lecture information on wave characteristics and properties, students take notes using a handout. Then they label wave parts on a worksheet diagram and draw their own waves with specified properties (crest, trough and wavelength). They also make observations about the waves they drew to determine which has the highest and the lowest frequency. With this knowledge, students better understand waves and are a step closer to understanding how humans see color.