Curricular Unit: MRI Safety Grand ChallengeContributed by: VU Bioengineering RET Program, School of Engineering, Vanderbilt University
This module was written for a first year accelerated or AP physics class. It is intended to provide hands on activities to teach end of the year electricity and magnetism topics including the magnetic force, magnetic moments and torque, the Biot-Savart law, Ampere's Law, and Faraday's Law. During the module, students utilize these scientific concepts to solve the following problem: A nearby hospital has just installed a new Magnetic Resonance Imaging facility, which has the capacity to make a three dimensional image of the brain and other parts of the body by putting a patient into a strong magnetic field. The hospital wishes for its entire staff to have a clear knowledge of the risks involved with working near a strong magnetic field, and a basic understanding of why those risks occur. Your task is to develop a presentation or pamphlet explaining the risks involved, the physics behind those risks, and the safety precautions that should be taken by all staff members. This module is built around the Legacy Cycle, a format that incorporates findings from educational research on how people best learn.
Time Required: 15 hours
Spread over 17 fifty-minute class periods
Related Subject Areas
Unit Overview (Return to Contents)
The design uses a contextually based "Challenge" followed by a sequence of instruction in which students first offer initial predictions ("Generate Ideas") and then gather information from multiple sources ("Multiple Perspectives"). This is followed by "Research and Revise" as students integrate and extend their knowledge through a variety of learning activities. The cycle concludes with formative ("Test Your Mettle") and summative ("Go Public") assessments that lead the student towards answering the Challenge question. See the unit overview below for the progression of the legacy cycle through the unit. Research and ideas behind this way of learning may be found in How People Learn, (Bransford, Brown & Cocking, National Academy Press, 2000); you may find the entire text on the web at http://www.nap.edu/openbook.php?isbn=0309070368.
The Legacy Cycle is similar to the Engineering Design Process in that they both involve identifying a need existing in society, combining science and math to develop solutions, and finally using the research conclusions to design a clear conceived solution to the original challenge. Though the engineering design process and the legacy cycle depend on a correct and accurate solution, each focuses particularly on how the solution is devised and presented. An overview of the Engineering Design Process can be found on the web at http://en.wikipedia.org/wiki/Engineering_design_process.
In Lesson 1, students will be prompted to answer the following Grand Challenge: A nearby hospital has just installed a new Magnetic Resonance Imaging facility, which has the capacity to make a three dimensional image of the brain and other parts of the body by putting a patient into a strong magnetic field. The hospital wishes for its entire staff to have a clear knowledge of the risks involved with working near a strong magnetic field, and a basic understanding of why those risks occur. Your task is to develop a presentation or pamphlet explaining the risks involved, the physics behind those risks, and the safety precautions that should be taken by all staff members.
Students will begin by Generating Ideas in a journal, answering questions such as, "What risk factors could a strong magnetic field pose to medical personnel?" Then students will be prompted to consider the perspective of an MRI researcher as part of the Multiple Perspectives step of the legacy cycle. Students will begin the Research and Revise phase with an activity at the end of the lesson to Visualize Magnetic Field Lines.
In Lesson 2, students will enter the Research and Revise step focusing on how a magnetic field affects charged particles with a Deflection of an Electron Beam Demonstration. With teacher instruction, students will review vector cross products and be introduced to the Lorentz force. Finally, students will participate in a Magnetic Force on a Current Carrying Wire activity. This lesson will be concluded with a Magnetic Fields and Forces Quiz as part of the Test your Mettle stage of the cycle.
Lesson 3 will return to the Research and Revise step for further learning. This lesson will include teacher instruction on Torque on a Current Loop and Energy of a Current Loop in a Magnetic Field with example problems.
Lesson 4 proceeds in the Research and Revise phase but introduces the concepts developed from the base knowledge taught in lesson 3. These concepts include the Hall Effect, Velocity Selector, and Charge to Mass Ratio.
In Lesson 5, students will focus on what produces a magnetic field through the magnetic field around a wire demo. This demonstration will be part of teaching students the Biot Savart Law in the Research and Revise phase.
In Lesson 6, students will continue learning what produces a magnetic field by studying the field of a solenoid in a slinky activity and relating it to the MRI machine.
In Lesson 7, still Researching and Revising, students being with a demonstration: Force Between Two Current Loops. Students are taught Ampere's law and then prompted to use the law to calculate the magnetic field around a loop. Torroids and their magnetic fields are then presented.
Lesson 8 teaches students induced EMFs with a demonstration on Eddy Currents and a demonstration inducing a jumping ring.
Lesson 9 discusses the effects of magnetic fields in matter, including diamagnetism, paramagnetism, ferromagnetism, and magnetization. Lesson 9 concludes the research and revise phase of the legacy cycle.
In Lesson 10, students enter the Test Your Mettle phase with a problem set on Ampere's Law, Faraday's Law, and the sources of magnetic field and induction. Finally, students Go Public with an informative project determining the possible hazards associated with the fields in an MRI scanner.
Assessment (Return to Contents)
Lesson 10 includes the final Go Public phase of the legacy cycle where students are prompted to apply the concepts they have learned to answer the Grand Challenge question. This allows students to relate electricity and magnetism to biomedical engineering by studying the risks associated with the strong magnetism of an MRI unit. Students will also be tested on their understanding of biomedical imaging as applicable to electricity and magnetism. This is a cumulative assessment covering all ten lessons.
ContributorsEric Appelt, Primary Author, Meghan Murphy
Copyright© 2006 by Vanderbilt University
Including copyrighted works from other educational institutions and/or U.S. government agencies; all rights reserved. The contents of this digital library curriculum were developed under a grant from the National Science Foundation RET grants no. 0338092 and 0742871. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.
Supporting ProgramVU Bioengineering RET Program, School of Engineering, Vanderbilt University
Last Modified: July 28, 2014