The invention is directed to a device and a method for carrying out experiments of chemical, biochemical, biological and physical analysis, reaction and assay employing a reaction unit, in a preferred embodiment comprising: a capillarity reaction chamber, non-capillarity zone and bottom structure, which can use capillary action to quantitatively take up by itself and hold liquid in the reaction chamber. A multi-unit plate, which contains a number of reaction units on a plate frame, can be used for parallel experiments in conjunction with reservoir plate, waster pad, and liquid transfer guider.