Teeth and bones are both hard, mineral-rich tissues, but they differ significantly in function, structure, and living tissue status. Teeth are primarily for digestion and speech, made of enamel, dentin, and pulp, and are non-living tissue once formed. Bones support the body, protect organs, and are living tissues that constantly remodel through blood vessels and cells, which teeth do not have. These differences explain why teeth are not classified as bones.
The debate over whether glass is a liquid or a solid continues, but scientists explain that glass is a distinct state of matter that exhibits properties of both. Glass is a noncrystalline, nonequilibrium material that appears solid on a short timescale but continuously relaxes towards a liquid state. It is made by melting various components to form a viscous liquid, which is then cooled quickly, trapping the atoms in a disordered arrangement. While glass may exhibit slow changes over billions of years, it behaves more like a solid than a liquid on practical timescales. The belief that medieval stained-glass windows are thicker at the bottom due to glass flowing over time is debunked, with the explanation being that glass manufacturing techniques at the time resulted in uneven thickness.
