dermatologist(n.) One who discourses on the skin and its diseases; one versed in dermatology; especially, a physician with specialized training in dermatology, licensed to practise as a specialist in treating diseases of the skin.
Melting Point: Everyday and Scientific Definitions. Now that we know something about phase diagrams, it will make more sense why scientists define melting point the way they do. First, in everyday terms, the melting point is the temperature at which a substance melts or freezes.
This generally leads to low melting points for covalent solids, and high melting points for ionic solids. For example, the molecule carbon tetrachloride is a non-polar covalent molecule, CCl4. It's melting point is -23Â°C. By contrast, the ionic solid NaCl has a melting point of 800Â°C.