Melting point of ice at 1 atmosphere of pressure is very close to ; this is also known as the ice point. In the presence of nucleating substances, the freezing point of water is not always the same as the melting point. In the absence of nucleators water can exist as a supercooled liquid down to −48.3 °C (−55 °F, 224.8 K) before freezing. The chemical element with the highest melting point is tungsten, at ; this property makes tungsten excellent for use as filaments in light bulbs. The often-cited carbon does not melt at ambient pressure but sublimes at about ;
Melting-point apparatus Melting-point apparatus A melting-point apparatus is a scientific instrument used to determine the melting point of a substance. Some types of melting-point apparatuses include the Thiele tube, Fisher-Johns apparatus, Gallenkamp (Electronic) melting-point apparatus and automatic melting-point apparatus. While the outward designs of apparatuses can vary greatly, most apparatuses use a sample loaded into a sealed capillary ("melting-point capillary"), which is then placed in the apparatus. The sample is then heated, either by a heating block or an oil bath, and as the temperature increases, the sample is observed to determine when the phase change from solid to liquid occurs. The