Students learn about various crystals, such as kidney stones, within the human body. They also learn about how crystals grow and ways to inhibit their growth. They also learn how researchers such as chemical engineers design drugs with the intent to inhibit crystal growth for medical treatment purposes and the factors they face when attempting to implement their designs. A day before presenting this lesson to students, conduct the associated activity, Rock Candy Your Body.

Students use a tension-compression machine (or an alternative bone-breaking setup) to see how different bones fracture differently and with different amounts of force, depending on their body locations. Teams determine bone mass and volume, calculate bone density, and predict fracture force. Then they each test a small animal bone (chicken, turkey, cat) to failure, examining the break to analyze the fracture type. Groups conduct research about biomedical challenges, materials and repair methods, and design repair treatment plans specific to their bones and fracture types, presenting their design recommendations to the class.

Students learn how forces affect the human skeletal system through fractures and why certain bones are more likely to break than others depending on their design and use in the body. They learn how engineers and doctors collaborate to design effective treatments with consideration for the location, fracture severity and patient age, as well as the use of biocompatible materials. Learning the lesson content prepares students for the associated activity in which they test small animal bones to failure and then design treatment repair plans.

Students are challenged to think as biomedical engineers and brainstorm ways to administer medication to a patient who is unable to swallow. They learn about the advantages and disadvantages of current drug delivery methods—oral, injection, topical, inhalation and suppository—and pharmaceutical design considerations, including toxicity, efficacy, size, solubility/bioavailability and drug release duration. They apply their prior knowledge about human anatomy, the circulatory system, polymers, crystals and stoichiometry to real-world biomedical applications. A Microsoft® PowerPoint® presentation and worksheets are provided. This lesson prepares students for the associated activity in which they create and test large-size drug encapsulation prototypes to provide the desired delayed release and duration timing.

Students learn how crystallization and inhibition occur by examining calcium oxalate crystals with and without inhibitors that are capable of altering crystallization. Kidney stones are composed of calcium oxalate crystals, and engineers and doctors experiment with these crystals to determine how growth is affected when a potential drug is introduced. Students play the role of engineers by trying to determine which inhibitor would be the best for blocking crystallization.

Students are introduced to prosthetics history, purpose and benefits, main components, main types, materials, control methods, modern examples including modern materials used to make replacement body parts and the engineering design considerations to develop prostheses. They learn how engineers and medical doctors work together to improve the lives of people with amputations and the challenges faced when designing new prostheses with functional and cosmetic criteria and constraints. A PowerPoint(TM) presentation and two worksheets are provided.

Students see and learn how crystallization and inhibition occur by making sugar crystals with and without additives in a supersaturation solution, testing to see how the additives may alter crystallization, such as by improving crystal growth by more or larger crystals. After three days, students analyze the differences between the control crystals and those grown with additives, researching and attempting to deduce why certain additives blocked crystallization, showed no change or improved growth. Students relate what they learn from the rock candy experimentation to engineering drug researchers who design medicines for targeted purposes in the human body. Conduct the first half of this activity one day before presenting the associated lesson, Body Full of Crystals. Then conduct the second half of the activity.

Students experience the engineering design process as they design, fabricate, test and redesign their own methods for encapsulation of a (hypothetical) new miracle drug. As if they are engineers, teams make large-size prototypes to test proof of concept. They use household materials (tape, paper towels, plastic wrap, weed-barrier fabric, glues, etc.) to attach a coating to a porous "shell" (a perforated plastic Wiffle® ball) containing the medicine (colored drink mix powder). The objective is to delay the drug release by a certain time and have a long release duration—patterned after the timed release requirements of many real-world pharmaceuticals that are released from a polymer shell via diffusion in the body. Guided by a worksheet, teams go through at least three design/test iterations, aiming to achieve a solution close to the target time release constraints.

Students experience the engineering design process as they design and construct lower-leg prostheses in response to a hypothetical zombie apocalypse scenario. Like the well-known Apollo 13 story during which engineers were challenged to fix the crippled spacecraft with limited supplies in order to save astronauts' lives, in this activity, students act as engineers during an imaginary disaster in which a group member's leg was amputated in order to survive a zombie attack. Building on what they learned and researched in the associated lesson, they design and fabricate a replacement prosthetic limb using given specific starting material and limited additional supplies, similar to how engineers design for individuals while working within constraints. A more-advanced scenario challenges students to design a prosthesis that is able to provide a more-specific movement function.