This is a numerical simulation illustrating Tomlinson's mechanism of friction on the nanoscale.

Single atom on a substrate 

Crystal on a substrate

Crystal and debris

Introducing a few atoms of debris between the substrate and the crystal again enables interlocking.  This time, it is the debris atoms that have favorable positions relative to the substrate and the crystal.  As they slip from one such position to the next, we observe the stcik-slip motion.  Static friction returns.

Suggested activity.  Determine the coefficient of static friction and compare it against the previous measurements


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The applets were created by Mark Robbins and Oleg Tchernyshyov with the aid of Easy Java Simulations.


Use Policy:  This text is copyrighted by Mark Robbins and Oleg Tchernyshyov.  Non-profit educational use is permitted with appropriate acknowledgement.

NSF logoThis material is based upon work supported by the National Science Foundation under Grants No. DMR-0348679 and DMR-0454947.  Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily
reflect the views of the National Science Foundation.