2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/117484We present experimental evidence for a first-order freezing/melting phase transition in a nonequilibrium system -- an oscillated two-dimensional isobaric granular fluid. The steady-state transition occurs between a gas and a crystal and is characterized by a discontinuous change in both density and temperature. It is suppressed if the number of particles is incommensurate with the cell size, shows rate-dependent hysteresis, and obeys the Lindemann criterion for melting. Further, the measured equation of state both above and below the phase transition compares well with theory.Soft Condensed MatterStatistical Mechanicstext