In metals, electrons are normally expected to be diffusive in their movement, operating as individual particles – in other words, they don't gain momentum as a group. In a new study, scientists have now discovered a type of metal where electrons actually do flow in a fluid-like way – like water in a pipe – by interacting with quasiparticles called phonons, which emerge from vibrations in a crystal structure. This causes the electrons to shift from diffusive (particle-like) to hydrodynamic (fluid-like) behavior in their movement. The metal superconductor that causes this behavior is a synthesis of niobium and germanium called...