The Advanced Labs website will be unavailable Friday evening through Saturday afternoon as electrical work occurs in the American Center of Physics server room. Down time will begin at 6PM Eastern Time on Friday. Service is expected to resume by 6PM on Saturday, July 30.

2009 Advanced Laboratories Conference Abstract Detail Page

Previous Page  |  New Search  |  Browse All

Abstract Title: A Knots Experiment
Abstract: Understanding how knots form and untie is crucial in understanding the biophysics of DNA or the structural properties of polymers, but it is very difficult to study these processes directly.  This experiment studies the dynamics of knots in granular chains  (the type used to hold drain plugs) on a plate vibrating at varying frequencies and amplitudes.  These chains are interesting in their own right, and the subject of a number or recent papers in Physical Review Letters and other major research journals.

Students explore how the unknotting time of the chain depends on different parameters such as length, frequency, amplitude, linear mass density, and number and type of knots. They can also examine the statistics of the unknotting process, study the radius-of-gyration and pattern formation in unknotted chains, and investigate other aspects of the shaker and its dynamical relation with a chain (or other materials) on its surface.  The phase space of possible measurements is very large, so students can explore many ideas of their own.  The experiment is a bit noisy, but is simple, inexpensive, and easy to use.  The challenge for the student is in the planning and analysis, and in having enough patience to take sufficient data.

The basic apparatus for the experiment will be demonstrated at the workshop. More information can be found at
Abstract Type: Poster
Contributed Poster: Download the Contributed Poster
Session: Session IX - Effective Experiments Poster Session

Author/Organizer Information

Primary Contact: David C. Bailey
University of Toronto
Physics Department
60 St. George Street
Toronto, Non U.S. M5S 1A7
Phone: 416-978-6674 or -4993
Fax: 416-978-8221
and Co-Presenter(s)
Jason J. B. Harlow, Physics Department, University of Toronto
Natalia N. Krasnopolskaia, Physics Department, University of Toronto
Stephen W. Morris,  Physics Department, University of Toronto