A sensitive differential scanning dilatometer for the study of the volume changes, mainly in aqueous dispersions and solutions, is presented. The volume changes in the sample during temperature scanning are compared with the changes in a solvent at the same temperature. The metal membranes take up the expansion and change the electrical capacitance between the membranes and their surrounding electrodes. The volume of two sample chambers is 1.5 ml, the sensitivity of the instrument is 2 nl in the temperature range (0-60)-degrees-C.