The Air-Conditioned Pyramid. An Analogy to Clarify the Main Concepts in Nuclear Magnetic Resonance

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 10 Issue 2 (2005) pp 82-83

The Air-Conditioned Pyramid. An Analogy to Clarify the Main Concepts in Nuclear Magnetic Resonance

Vladimir N. Garkov

Mary Baldwin College, Staunton, VA 24401, vgarkov@mbc.edu
Received November 4, 2004. Accepted January 30, 2005.

Published online: 3 February 2005

Abstract. An analogy that may be helpful for an understanding of NMR terminology and concepts is described. A group of college students (nuclei of the chemical compound to be analyzed), each of whom is wearing a different amount of clothing (level of shielding) are on a visit to an air-conditioned pyramid. This pyramid consists of 100 interconnected rooms, each with a specific constant temperature corresponding to the room number and varying from 0 °F in the penthouse (the zero room) of the top floor (upfield) to 100 °F in the last room on the lowest or 10th floor (downfield). This temperature variation is maintained by a respective level of air-conditioning (strength of the externally applied magnetic field), which operates at its highest at the top of the pyramid (high field) and gradually decreases as one descends towards the bottom of the pyramid (low field). Starting with the coldest room (the penthouse), all students (nuclei) move gradually down the pyramid from one room to the next to find the room that corresponds to their level of clothing (shielding). There they put on headphones and start listening to the radio program that tells the story of the pyramid (nuclei in resonance with the constant radio frequency energy).

Key Words: In the Classroom; general chemistry; high school chemistry; NMR

(*) Corresponding author. (E-mail: vgarkov@mbc.edu)

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