Heating and cooling curves

This test enables to plot the heating and cooling curves of a pure substance. The method applied will allow to observe either the phase transition of a pure substance from solid state to liquid state, and the opposite phase transition. The trend of these curves leads to notice that the progressive heating provokes a regular rise of the temperature of the substance. This trend is interrupted by the fusion or by the solidification. Both these phase transitions occur at the same temperature. Comparing the heating curves of water and of paradichlorobenzene will lead to realize that the hot plate outputs a constant heat flow inducing a regular temperature elevation (water heating curve); as regards the substance, the isothermal period is pointed out in both the heating and cooling phases.