A method for ascertaining a physical parameter of a liquid, which has a gas charge using a measuring transducer having a measuring tube for conveying the medium. The measuring tube executes oscillations in bending oscillation mode. The method includes: exciting the measuring tube with an eigenfrequency of a bending oscillation mode—or f1-mode, ascertaining a suppressed excitation frequency, at which the oscillation amplitude of the measuring tube is minimum; identifying the frequency as the resonant frequency of the gas-charged liquid; ascertaining a density correction term as a function of the resonant frequency for correcting a preliminary density measured value and/or mass flow correction term as a function of the resonant frequency for correcting a preliminary mass flow rate measured value, and/or ascertaining the velocity of sound in the gas-charged liquid in the measuring tube as a function of the resonant frequency.