Final answer:
Materials like metals, ceramics, and polymers are classified by their unique properties: metals conduct heat and electricity, ceramics are insulative and brittle, and polymers are moldable and vary in their response to heat.
Step-by-step explanation:
Definitions and Characteristics of Materials
To classify materials as metals, ceramics, or polymers, we must identify their distinct characteristics. Metals are characterized by their ability to conduct heat and electricity, their malleability, and ductility. They often have a high melting and boiling point. Ceramics are typically inorganic compounds that are thermal and electrical insulators, brittle, and stable at high temperatures. Polymers are large molecules composed of repeating subunits, which can be classified as thermoplastics or thermosets based on their response to heat.
Classifications and Justifications
Materials such as gold are categorized as metals due to their high electrical conductivity and malleability. Porcelain, an example of a ceramic, is an electrical insulator and prone to fracture under tension, highlighting its brittle nature. Polymers like polyethylene are classified by their ability to be molded upon heating (thermoplastic) and returning to a solid state upon cooling.