Magnetohydrodynamic Propulsion for the Classroom

The cinema industry can sometimes prove to be an ally when searching for material with which to motivate students to learn physics. Consider, for example, the electromagnetic force on a current in the presence of a magnetic field. This phenomenon is at the heart of magnetohydrodynamic (MHD) propulsion systems. A submarine employing this type of propulsion was immortalized in the movie Hunt for Red October.¹ While mentioning this to students certainly gets their attention, it often elicits comments that it is only fiction and not physically possible. Imagine their surprise when a working system is demonstrated! It is neither difficult nor expensive to construct a working system that can be demonstrated in the front of a classroom.² In addition, all aspects of the engineering hurdles that must be surmounted and myths concerning this "silent propulsion" system are borne out in a simple apparatus. This paper details how to construct an inexpensive MHD propulsion boat that can be demonstrated for students in the classroom. ©2004 American Association of Physics Teachers

Contents

• BODY OF ARTICLE
• Physics of Magnetohydrodynamic Propulsion
• MHD Boat Design
• Optimization of the MHD Boat Design
• Building and Operating the MHD Boat
• Myths and Monsters
• Summary
• REFERENCES
• About the Author
• FIGURES