Advanced Undergraduate Laboratory

Department of Physics

University of Toronto

KNOT: Knots and topological transformations in vibrating chains

How knots tied in metal chains untie themselves when vibrated is way to study how important macromolecules such as polymers and DNA tangle and untangle. Nontrivial knots of one-dimensional objects only exist in three spatial dimensions, which may explain why our universe has three dimensions.

In this seemly simple experiment you will explore the challenging mechanics and thermodynamics of linear chains. The experiment is originally based on Knots and Random Walks in Vibrated Granular Chains, E. Ben-Naim et al., Phys. Rev. Lett. 86 (2001) 1414.

Write-Up in PDF Format or Microsoft Word Format.

(The experiment is currently located in MP239; last write-up revision: September 2015.)

Additional resources:

Photo of student working on Knots experiment
Physics student Myles Casey-Nestor working on the Knots experiment.

Unknotting simulation from

Last updated on 12 May 2021