Capillary flow of 0.3% aqueous solutions of poly(ethylene oxide), 4×106MW, generates a fluctuating electrical signal (noise) between electrodes at the ends of the capillary. The frequency spectra of the noise are approximately of the 1/f &agr;type. Within certain flow rate ranges, two sets of harmonic peaks appear in the spectra. It is shown that these peaks are associated with the transverse and longitudinal modes of motion of the elastic solution entering the capillary. This equivalence has been verified by frequency analysis of the intensity of a laser beam transmitted through the entry region, and by high‐speed photography. The noise is assumed to reflect fluctuations in the streaming potential, caused by fluctuations in flow rate.