Method of changing a property of a polar liquid

For changing a property of a polar liquid a device comprising a signal generator and a transducer is provided adjacent to the liquid or at least partially immersed therein. The signal generator provides an alternating electrical signal to the transducer, wherein the electrical signal is of a frequency and an amplitude to affect the transducer to produce an alternating magnetic field having a magnetic flux density so as to change the property of the polar liquid, wherein a portion of the magnetic field penetrates the liquid, having an effect thereon and providing a change in the property of the liquid at a distance of at least 1 meter from the transducer. The property is a gas exchange rate and the change is at least 5%, or the property is surface tension and the change is at least 1%, or the property is viscosity and the change is at least 0.5%.