Why is ice so slippery?

The answer lies in a film of water that is generated by friction, one that is far thinner than expected and much more viscous than usual water through its resemblance to the "snow cones" of crushed ice we drink during the ...

How to control friction in topological insulators

Topological insulators are innovative materials that conduct electricity on the surface, but act as insulators on the inside. Physicists at the University of Basel and the Istanbul Technical University have begun investigating ...

Solving the pancake problem

If you swirl a glass of wine clockwise, the wine inside will also rotate clockwise. But, if you're making a blueberry pancake and you swirl the pan clockwise, the pancake will rotate counterclockwise. Don't believe us? Go ...

Are we at the limits of measuring water-repellent surfaces?

How liquids are repelled by a surface, a property called "wettability," is important for engineers to develop aircraft that resist ice formation, for fashion designers developing outdoor gear that repels rain and dirt, and ...

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Friction

Friction is the force resisting the relative lateral (tangential) motion of solid surfaces, fluid layers, or material elements in contact. It is usually subdivided into several varieties:

Friction is not a fundamental force, as it is derived from electromagnetic force between charged particles, including electrons, protons, atoms, and molecules, and so cannot be calculated from first principles, but instead must be found empirically. When contacting surfaces move relative to each other, the friction between the two surfaces converts kinetic energy into thermal energy, or heat. Contrary to earlier explanations, kinetic friction is now understood not to be caused by surface roughness but by chemical bonding between the surfaces. Surface roughness and contact area, however, do affect kinetic friction for micro- and nano-scale objects where surface area forces dominate inertial forces.

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