  In this paper, we experimentally explore the formation, evolution and breakup
of Armstrong liquid bridge. The extremely complicated evolution stage is
revealed, which involves many coupled processes including the morphology
change, current variation, heat transfer, and water evaporation. By focusing on
the final fate of this liquid bridge, we observe that the breakup occurs once
an effective length ($\tilde{L}$) is reached. This effective length increases
linearly with the applied voltage, implying a threshold electric field to
sustain the liquid bridge. Moreover, by an introduced external flow, the
lifetime of the liquid bridge can be controlled, while the effective length
associated with the breakup is independent on the external flow rate. Hence,
these findings remarkably demonstrate that the breakup of liquid bridge is
directly correlated with the effective length. In order to understand this
correlation, a simplified model of an electrified jet is employed to take the
electric field into account. By the linear stability analysis, the attained
phase diagram agrees with the experiments well. Although a more comprehensive
theory is required to consider other factors such as the surface charges, these
results might provide a fresh perspective on the ``century-old" Armstrong
liquid bridge to further elucidate its underlying physical mechanism.
