How can a horde of active robots be automatically brought to a standstill? By arresting their dynamics in a self-sustained ...

Robots acting as macroscale analogs of active nanoparticles stop moving through friction alone, revealing a self-sustained ...

The sideways pushing force from the finger. There MUST be a backwards pushing force to cancel the finger force. This is the static friction force. OK, time for the next experiment.

More information: Krittanon Sirorattanakul et al, Sliding and healing of frictional interfaces that appear stationary, Nature (2025). DOI: 10.1038/s41586-025-08673-0 ...

Local Shearing Force Measurement during Frictional Sliding Using Fluorogenic Mechanophores. The Journal of Physical Chemistry Letters, 2022; 8840 DOI: 10.1021/acs.jpclett.2c02010 ...

More surprising, friction can exist even between bodies that make no contact whatsoever. For example, measurements of the force required to drag the aluminium tip of a scanning tunnelling ...

Friction is a force between two surfaces that are sliding, or trying to slide, across each other. You can find out more using this Bitesize KS2 Science guide.