How can a horde of active robots be automatically brought to a standstill? By arresting their dynamics in a self-sustained way. This phenomenon was discovered by physicists at Heinrich Heine ...

Irregularities present on a surface are often described as surface roughness or texture. These surface textures such as grooves and dimples impart friction, which is the force between two sliding ...

Because of friction, sleds don't technically touch the snow and instead ride on a small layer of water created by the heat of the sled sliding down the hill. Sledding is one of many ways Wisconsinites ...