Thiele Tube for Melting Point Determinations

Laboratory equipment for the determination of the melting point of substances The Thiele tube is a specialized glass instrument that facilitates controlled heating using a thermal oil bath. Its characteristic structure features a main tube accompanied by a triangular-shaped side arm that allows the continuous circulation of the fluid in a closed circuit. This device is used to identify the melting and boiling temperatures in previously pulverized solid samples. The preparation of the sample requires its reduction to fine powder using a mortar, material which is subsequently introduced into a capillary tube closed at one of its ends. The Thiele tube is vertically stabilized using a base support, rod, and clamp. Once the equipment is positioned, it is filled with mineral oil, submerging both the capillary tube with the sample and a thermometer, which is held in place by a rubber stopper in the upper opening of the device. Heating is performed by applying a direct heat source to the triangular side arm, an action that promotes the formation of convection currents that uniformly distribute the oil's temperature. The melting point is determined by observing the moment the sample transitions to the liquid state, recording the thermometer reading at that instant.