Schematic of the convection cell. (a) Isometric view. (b) Exploded frontal view. The cell is composed by (1) a plate at higher temperature, (2) a plate at lower temperature and (3) perspex lateral walls which confine the (4) fluid layer of height d. Two conducts in the lateral walls (5-6) allow the filling of the cell and account the thermal expansion of the fluid. A system of (7) hoses and (8) diffuser distributes cooling water to the plate at lower temperatura, where it circulates in 8 channels in counterflow. A (9) film heater provides heat to the plate at higher temperature. Both plates have (10-11) perforations to place temperature sensors. In figures (a-b) the color of the hoses indicate the incoming and exit of cooling water at lower and higher temperatures