To gain a better understanding of the roles and functions of components of the human respiratory system and our need for clean air, students construct model lungs that include a diaphragm and chest cavity. They see how air moving in and out of the lungs coincides with diaphragm movement. Then student teams design and build a prototype face mask pollution filter. They use their model lungs to evaluate their prototypes to design requirements.

Student teams investigate biomedical engineering and the technology of prosthetics. Students create a model prosthetic lower leg using various materials. Each team demonstrate its prosthesis' strength and consider its pros and cons, giving insight into the characteristics and materials biomedical engineers consider in designing artificial limbs.

Students reinforce their knowledge of the different parts of the digestive system and explore the concept of simulation by developing a pill coating that can withstand the churning actions and acidic environment found in the stomach. Teams test the coating durability by using a clear soda to simulate stomach acid.

Students design and build prototypes for protective eyewear. They choose different activities or sports that require protective eyewear and design a device for that particular use. Students learn about the many ways in which the eyes can be damaged and how engineers incorporate different features and materials into eyewear designs to best protect the eyes.

In this activity, learners explore their eye pupils and how they change. Learners use a magnifying glass, mirror, and flashlight to observe how their pupil changes size in response to changes in lighting. Learners also experiment to determine how light shining in one eye affects the size of the pupil in their other eye. This resource guide includes background information about pupils and why they change as well as information related to emotional stimuli, involuntary reflexes, and photography.

Students observe and test their reflexes, including the (involuntary) pupillary response and (voluntary) reaction times using their dominant and non-dominant hands, as a way to further explore how reflexes occur in humans. They gain insights into how our bodies react to stimuli, and how some reactions and body movements are controlled automatically, without conscious thought. Using information from the associated lesson about how robots react to situations, including the stimulus-to-response framework, students see how engineers use human reflexes as examples for controls for robots.

Students learn about human reflexes, how our bodies react to stimuli and how some body reactions and movements are controlled automatically, without thinking consciously about the movement or responses. In the associated activity, students explore how reflexes work in the human body by observing an involuntary human reflex and testing their own reaction times using dominant and non-dominant hands. Once students understand the stimulus-to-response framework components as a way to describe human reflexes and reactions in certain situations, they connect this knowledge to how robots can be programmed to conduct similar reactions.

Students learn about how biomedical engineers aid doctors in repairing severely broken bones. They learn about using pins, plates, rods and screws to repair fractures. They do this by designing, creating and testing their own prototype devices to repair broken turkey bones.

Students continue to build a rigorous background in human sensors and their engineering equivalents by learning about electronic touch, light, sound and ultrasonic sensors that measure physical quantities somewhat like eyes, ears and skin. Specifically, they learn about microphones as one example of sound sensors, how sounds differ (intensity, pitch) and the components of sound waves (wavelength, period, frequency, amplitude). Using microphones connected to computers running (free) Audacity® software, student teams experiment with machine-generated sounds and their own voices and observe the resulting sound waves on the screen, helping them to understand that sounds are waves. Students take pre/post quizzes, complete a worksheet and watch two short online videos about "seeing" sound.

Students use their knowledge about how healthy heart valves function to design, construct and implant prototype replacement mitral valves for hypothetical patients' hearts. Building on what they learned in the associated lesson about artificial heart valves, combined with the testing and scoring of their prototype heart valve designs in this activity, students discover the pros and cons of different types of artificial heart valves based on materials, surgery requirements, and lifespan.

In this quick optics activity, learners use a dim point of light (a disassembled Mini MagLite and dowel set-up) to cast a shadow of the blood supply in their retina onto the retina itself. This allows learners to see the blood supply of their retina and even their blind spot. Learners are encouraged to wear eye protection.

Towards finding a solution to the unit's Grand Challenge Question about using nanoparticles to detect, treat and protect against skin cancer, students continue the research phase in order to answer the next research questions: What is the structure and function of skin? How does UV radiation affect the chemical reactions that go on within the skin? After seeing an ultraviolet-sensitive bead change color and learning how they work, students learn about skin anatomy and the effects of ultraviolet radiation on human skin, pollution's damaging effect on the ozone layer that can lead to increases in skin cancer, the UV index, types of skin cancer, ABCDEs of mole and lesion evaluation, and the sun protection factor (SPF) rating system for sunscreens. This prepares students to conduct the associated activity, in which they design quality-control experiments to test SPF substances.

Students review what they know about the 20 major bones in the human body (names, shapes, functions, locations, as learned in the associated lesson) and the concept of density (mass per unit of volume). Then student pairs calculate the densities for different bones from a disarticulated human skeleton model of fabricated bones, making measurements via triple-beam balance (for mass) and water displacement (for volume). All groups share their results with the class in order to collectively determine the densities for every major bone in the body. This activity prepares students for the next activity, "Can It Support You? No Bones about It," during which they act as biomedical engineers and design artificial bones, which requires them to find materials of suitable density to perform as human body implants.

Why do humans have two ears? How do the properties of sound help with directional hearing? Students learn about directional hearing and how our brains determine the direction of sounds by the difference in time between arrival of sound waves at our right and left ears. Student pairs use experimental set-ups that include the headset portions of stethoscopes to investigate directional hearing by testing each other's ability to identify the direction from which sounds originate.

Students follow the steps of the engineering design process to create their own ear trumpet devices (used before modern-day hearing aids), including testing them with a set of reproducible sounds. They learn to recognize different pitches, and see how engineers must test designs and materials to achieve the best amplifying properties.

This lesson introduces students to the space environment. It covers the major differences between the environment on Earth and that of outer space and the engineering challenges that arise because of these discrepancies. In order to prepare students for the upcoming lessons on the human body, this lesson challenges them to think about how their bodies would change and adapt in the unique environment of space.

Students learn about the strength of bones and methods of helping to mend fractured bones. During a class demonstration, a chicken bone is broken by applying a load until it reaches a point of failure (fracture). Then, working as biomedical engineers, students teams design their own splint or cast to help repair a fractured bone, learning about the strength of materials used.

With the challenge to program computers to mimic the human reaction after touching a hot object, students program LEGO® robots to "react" and move back quickly once their touch sensors bump into something. By relating human senses to electronic sensors used in robots, students see the similarities between the human brain and its engineering counterpart, the computer, and come to better understand the functioning of sensors in both applications. They apply an understanding of the human "stimulus-sensor-coordinator-effector-response" framework to logically understand human and robot actions.

Students learn about glaucoma its causes, how it affects individuals and how biomedical engineers can identify factors that trigger or cause this eye disease, specifically the increase of pressure in the eye. Students also learn how RFID technologies transfer energy through waves and how engineers apply their scientific understanding of waves, energy and sensors to develop devices that measure the pressure in the eyes of people with glaucoma. Students conclude by sketching their own designs for a pressure-measuring eye device, preparing them to conduct the associated activity in which they revise, prototype and evaluate their device designs made tangible with a 3D printer.

Students reflect on their experiences making silly putty (the previous hands-on activity in the unit), especially why changing the borax concentration alters the mechanical properties of silly putty and how this pertains to tissue mechanics. Students learn why engineers must understand tissue mechanics in order to design devices that will be implanted or used inside bodies, to study pathologies of tissues and how this alters tissue function, and to design prosthetics. Finally, students learn about collagen, elastin and proteoglycans and their roles in giving body tissues their unique functions. This prepares them for the culminating design-build-test activity of the unit.