Abstract: The invention describes a method and a device for simultaneously determining the mass, volumes or types of substance samples in a plurality of small cavities (2), particularly of wells in microtiter plates. According to the method, energy is supplied by an energy source (5) to the wells, which are partially or completely filled with samples. Depending on the mass thereof, the samples thus heat up more or less strongly. The determination of the substance volumes in the individual cavities is therefore based on temperature measurement. The simultaneous capturing of the sample temperature in the individual cavities can advantageously be performed by an infrared camera functioning as a detector (6). By implementing suitable calibration and measurement routines in an evaluation unit (7), the entire system, which substantially comprises an energy source and a detector, can be configured such that the substance volumes in the individual cavities are displayed directly.