Glass artifacts

Since glass is strong and non-reactive, it is a very useful object. Many household objects are made of glass. Drinking glasses, bowls, and bottles are frequently made of glass, as are light bulbs, mirrors, cathode ray tubes, and windows. In laboratories doing research in chemistry, biology, physics and lots of other fields, flasks, test tubes, lenses and other laboratory equipment are often made of glass. For these applications, borosilicate glass (such as Pyrex) is regularly used for its strength and low coefficient of thermal expansion, which gives greater resistance to thermal shock and allows for greater accuracy in laboratory measurements when heating and cooling experiments. For the most difficult applications, quartz glass is used, although it is very difficult to work. Most such glass is mass-produced using a variety of industrial processes, but most large laboratories need so much custom glassware that they keep a glassblower on staff. Volcanic glasses, such as obsidian, have long been used to make stone tools, and flint knapping techniques can simply be adapted to mass-produced glass.