Can It Support You? No Bones about It!
Biomedical engineers design implants for the body to help people to stay healthy and active for as long as possible!Copyright (top) 2006 National Institutes of Health, U.S. Department of Health & Human Services, Wikimedia Commons; (bottom) 2013 Science and Society Picture Library, Science Museum London, Wikimedia Commons http://en.wikipedia.org/wiki/Hip_replacement#mediaviewer/File:Hip_replacement_Image_3684-PH.jpg http://commons.wikimedia.org/wiki/Category:Hip_replacement#mediaviewer/File:Stainless_steel_and_ultra_high_molecular_weight_polythene_hip_replacement_(9672239334).jpg
After completing the associated lesson and its first associated activity, students are familiar with the 20 major bones in the human body—knowing their locations and relative densities. When those bones break, lose their densities or are destroyed, we look to biomedical engineers to provide replacements. In this activity, student pairs are challenged to choose materials and create prototypes that could replace specific bones. They follow the steps of the engineering design process, researching, brainstorming, prototyping and testing to find bone replacement solutions. Specifically, they focus on identifying substances that when combined into a creative design might provide the same density (and thus strength and support) as their natural counterparts. After iterations to improve their designs, they present their bone alternative solutions to the rest of the class. They refer to the measured and calculated densities for fabricated human bones calculated in the previous activity, and conduct Internet research to learn the densities of given fabrication materials (or measure/calculate those densities if not found online).
Biomedical engineers strive to come up with bone implant alternatives to assist people who injure themselves beyond repair of their natural bones, such as hip and knee replacements. Understanding the properties and behavior of materials is vital to the design of human implant materials. Choosing, or inventing, suitable materials to place in the human body is a challenging task faced by biomedical engineers. Biomedical engineers have successfully used a wide range of metal alloys, ceramics, polymers and composites as implantable materials.
After this activity, students should be able to:
- Use a computer to research materials (other than bones) and their densities.
- Determine the mass and volume needed to have the same density as the bone it may replace.
- Follow the steps of the engineering design process to find alternate materials and a design to replace a specific bone.
- Present findings to an audience through an oral and visual five-minute presentation.