Glass

Glass is an <a href="/facts/Amorphous/YTIzmrR0">amorphous</a> (<a href="/facts/Non-crystalline_solid/YTIzmrR0">non-crystalline</a>) solid. Because it is often <a href="/facts/Transparency_and_translucency/PRryNNW6">transparent</a> and chemically inert, glass has found widespread practical, technological, and decorative use in <a href="/facts/Window/d89WmHTN">window</a> panes, <a href="/facts/Tableware/fsIHo0nA">tableware</a>, and <a href="/facts/Optics/p0vq4S1T">optics</a>. Some common objects made of glass are named after the material, e.g., a <a href="/facts/Tumbler_(glass)/XXkGCzyt">"glass"</a> for drinking, "<a href="/facts/Glasses/ER3sFKmJ">glasses</a>" for vision correction, and a "<a href="/facts/Magnifying_glass/3fLtnXwp">magnifying glass</a>".
Glass is most often formed by rapid cooling (<a href="/facts/Quenching/UUCW0GQD">quenching</a>) of the <a href="/facts/Melting/zhhDBo5V">molten</a> form. Some glasses such as <a href="/facts/Volcanic_glass/MFmUlyad">volcanic glass</a> are naturally occurring, and <a href="/facts/Obsidian/GW1DI93A">obsidian</a> has been used to make arrowheads and knives since the <a href="/facts/Stone_Age/r1KMneWW">Stone Age</a>. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in <a href="/facts/Mesopotamia/f0mmbhTK">Mesopotamia</a>, <a href="/facts/Ancient_Egypt/BDsEGK4g">Egypt</a>, or <a href="/facts/Syria/7pDXGzq8">Syria</a>. The earliest known glass objects were <a href="/facts/Beads/lfI6rEzk">beads</a>, perhaps created accidentally during <a href="/facts/Metalworking/eAT0Pvz2">metalworking</a> or the production of <a href="/facts/Faience/Tlb7dgFh">faience</a>, which is a form of pottery using lead glazes.
Due to its ease of <a href="/facts/Formability/YqxzqpIM">formability</a> into any shape, glass has been traditionally used for vessels, such as <a href="/facts/Bowl_(vessel)/jEfbsyws">bowls</a>, <a href="/facts/Vase/f4VvNSEH">vases</a>, <a href="/facts/Bottle/TfyKYYKb">bottles</a>, jars and drinking glasses. <a href="/facts/Soda%E2%80%93lime_glass/CFYbacLU">Soda–lime glass</a>, containing around 70% <a href="/facts/Silicon_dioxide/A3WILp6J">silica</a>, accounts for around 90% of modern manufactured glass. Glass can be coloured by adding metal salts or painted and printed with <a href="/facts/Vitreous_enamel/gjfb1hA8">vitreous enamels</a>, leading to its use in <a href="/facts/Stained_glass/oUCut2Mc">stained glass</a> windows and other <a href="/facts/Glass_art/hmphBddU">glass art</a> objects.
The <a href="/facts/Refraction/S8kvSKzM">refractive</a>, <a href="/facts/Reflection_(physics)/BhcjDs79">reflective</a> and <a href="/facts/Transmission_coefficient/893q1h2K">transmission</a> properties of glass make glass suitable for manufacturing <a href="/facts/Lens_(optics)/ejlH6n5c">optical lenses</a>, <a href="/facts/Prism_(optics)/eodBFF70">prisms</a>, and <a href="/facts/Optoelectronics/0SCr9px0">optoelectronics</a> materials. Extruded <a href="/facts/Glass_fiber/IDL9pucz">glass fibres</a> have applications as <a href="/facts/Optical_fiber/5ruuIFbj">optical fibres</a> in communications networks, thermal insulating material when matted as <a href="/facts/Glass_wool/AQa67mn7">glass wool</a> to trap air, or in glass-fibre reinforced plastic (<a href="/facts/Fiberglass/T6MtJ4ep">fibreglass</a>).

Glass open-in-new

Glass