In this two-part activity, students design and build Rube Goldberg machines. This open-ended challenge employs the engineering design process and may have a pre-determined purpose, such as rolling a marble into a cup from a distance, or let students decide the purposes.

Students are introduced to engineering, specifically to biomedical engineering and the engineering design process, through a short lecture and an associated hands-on activity in which they design their own medical devices for retrieving foreign bodies from the ear canal. Through the lesson, they learn the basics of ear anatomy and how ear infections occur and are treated. Besides antibiotic treatment, the most common treatment for chronic ear infections is the insertion of ear tubes to drain fluid from the middle ear space to relieve pressure on the ear drum. Medical devices for this procedure, a very common children's surgery, are limited, sometimes resulting in unnecessary complications from a simple procedure. Thus, biomedical engineers must think creatively to develop new solutions (that is, new and improved medical devices/instruments) for inserting ear tubes into the ear drum. The class learns the engineering design process from this ear tube example of a medical device design problem. In the associated activity, students explore biomedical engineering on their own by designing prototype medical devices to solve another ear problem commonly experienced by children: the lodging of a foreign body (such as a pebble, bead or popcorn kernel) in the ear canal. The activity concludes by teams sharing and verbally analyzing their devices.

Student teams create laparoscopic surgical robots designed to reduce the invasiveness of diagnosing endometriosis and investigate how the disease forms and spreads. Using a synthetic abdominal cavity simulator, students test and iterate their remotely controlled, camera-toting prototype devices, which must fit through small incisions, inspect the organs and tissue for disease, obtain biopsies, and monitor via ongoing wireless image-taking. Note: This activity is the core design project for a semester-long, three-credit high school engineering course. Refer to the associated curricular unit for preparatory lessons and activities.

Students find and calculate the angle that light is transmitted through a holographic diffraction grating using trigonometry. After finding this angle, student teams design and build their own spectrographs, researching and designing a ground- or space-based mission using their creation. At project end, teams present their findings to the class, as if they were making an engineering conference presentation. Student must have completed the associated Building a Fancy Spectrograph activity before attempting this activity.

Students are challenged to design a permanent guest village within the Saguaro National Park in Arizona. The design must provide a true desert experience to visitors while emphasizing sustainable design, protection of the natural environment, and energy and resource conservation. To successfully address and respond to this challenge, students must acquire an understanding of desert ecology, environmental limiting factors, species adaptations and resource utilization. Following theintroduction, students generate ideas and consider the knowledge required to complete the challenge. The lectures and activities that follow serve to develop this level of comprehension. To introduce the concepts of healthy ecosystems, biomimetics and the importance of sustainable environmental design, students watch three video clips of experts. These clips provide direction for student research and challenge design solutions.

Students investigate circuits and their components by building a basic thermostat. They learn why key parts are necessary for the circuit to function, and alter the circuit to optimize the thermostat temperature range. They also gain an awareness of how electrical engineers design circuits for the countless electronic products in our world.

The Challenge Question of the Legacy Cycle draws the student into considering the engineering ingenuity of nature. It will force him to analyze, appreciate and understand the wisdom of these designs as the student team focuses on meeting each of the challenge's requirements. The student is asked, with his team members, to envision a sustainable design for a future guest village within the Saguaro National Park, outside of Tucson, Arizona. What issues need to be addressed to support the comforts of park visitors without compromising the natural resources or endangering the endemic species of the area? A deeper scope of application will reveal extensions of this design in the incorporation of urban planning and systems design. It also strengthens the concept of manufacturing and building without producing waste or pollution.

Students learn about the mathematical characteristics and reflective property of ellipses by building their own elliptical-shaped pool tables. After a slide presentation introduction to ellipses, student “engineering teams” follow the steps of the engineering design process to develop prototypes, which they research, plan, sketch, build, test, refine, and then demonstrate, compare and share with the class. Using these tables as models to explore the geometric shape of ellipses, they experience how particles rebound off the curved ellipse sides and what happens if particles travel through the foci. They learn that if a particle travels through one focal point, then it will travel through the second focal point regardless of what direction the particle travels.

Students are introduced to detail drawings and the importance of clearly documenting and communicating their designs. They are introduced to the American National Standards Institute (ANSI) Y14.5 standard, which controls how engineers communicate and archive design information. They are introduced to standard paper sizes and drawing view conventions, which are major components of the Y14.5 standard.

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.

Students use two different methods to determine the densities of a variety of materials and objects. The first method involves direct measurement of the volumes of objects that have simple geometric shapes. The second is the water displacement method, used to determine the volumes of irregularly shaped objects. After the densities are determined, students create x-y scatter graphs of mass versus volume, which reveal that objects with densities less than water (floaters) lie above the graph's diagonal (representing the density of water), and those with densities greater than water (sinkers) lie below the diagonal.

Geographic information systems (GIS), once used predominantly by experts in cartography and computer programming, have become pervasive in everyday business and consumer use. This unit explores GIS in general as a technology about which much more can be learned, and it also explores applications of that technology. Students experience GIS technology through the use of Google Earth on the environmental topic of plastics in the ocean in an area known as the Great Pacific Garbage Patch. The use of this topic in GIS makes the unit multidisciplinary, incorporating the physics of ocean currents, the chemistry associated with pollutant degradation and chemical sorption to organic-rich plastics, and ecological impact to aquatic biota.

Students create model elevator carriages and calibrate them, similar to the work of design and quality control engineers. Students use measurements from rotary encoders to recreate the task of calibrating elevators for a high-rise building. They translate the rotations from an encoder to correspond to the heights of different floors in a hypothetical multi-story building. Students also determine the accuracy of their model elevators in getting passengers to their correct destinations.

With a simple demonstration activity, students are introduced to the concept of friction as a force that impedes motion when two surfaces are in contact. Then, in the Associated Activity (Sliding and Stuttering), they work in teams to use a spring scale to drag an object such as a ceramic coffee cup along a table top or the floor. The spring scale allows them to measure the frictional force that exists between the moving cup and the surface it slides on. By modifying the bottom surface of the cup, students can find out what kinds of surfaces generate more or less friction. They also discover that both static and kinetic friction are involved when an object initially at rest is caused to slide across a surface.

Students explore the concept of optical character recognition (OCR) in a problem-solving environment. They research OCR and OCR techniques and then apply those methods to the design challenge by developing algorithms capable of correctly "reading" a number on a typical high school sports scoreboard. Students use the structure of the engineering design process to guide them to develop successful algorithms. In the associated activity, student groups implement, test and revise their algorithms. This software design lesson/activity set is designed to be part of a Java programming class.

Using the same method for measuring friction that was used in the previous lesson (Discovering Friction), students design and conduct experiments to determine if the amount of area over which an object contacts a surface it is moving across affects the amount of friction encountered.

Testing is critical to any design, whether the creation of new software or a bridge across a wide river. Despite risking the quality of the design, the testing stage is often hurried in order to get products to market. In this lesson, students focus on the testing phase of the software/systems design process. They start by exploring existing examples of program testing using the CodingBat website, which contains a series of problems and challenges that students solve using the Java programming language. Working in teams, students practice writing test cases for other groups' code, and then write test cases for a program before writing the program itself.

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.

Using the same method for measuring friction that was used in the previous lesson (Discovering Friction), students design and conduct an experiment to determine if weight added incrementally to an object affects the amount of friction encountered when it slides across a flat surface. After graphing the data from their experiments, students can calculate the coefficients of friction between the object and the surface it moved upon, for both static and kinetic friction.

In the first part of the activity, each student chews a piece of gum until it loses its sweetness, and then leaves the gum to dry for several days before weighing it to determine the amount of mass lost. This mass corresponds to the amount of sugar in the gum, and can be compared to the amount stated on the package label. In the second part of the activity, students work in groups to design and conduct new experiments based on questions of their own choosing. These questions arise naturally from observations during the first experiment, and from students' own experiences with and knowledge of the many varieties of chewing and bubble gums available.