Glass is a non-crystalline, often transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes and optically transparent materials. Glass can be colored by adding metallic salts, and can also be painted and printed with vitreous enamels. These qualities have led to the extensive use of glass in the manufacture of art objects.
The most familiar type of glass is an alkali-lime glass known as soda-lime glass (also called "soda lime"), composed of approximately 70% silica sand (SiO2), sodium carbonate (Na2CO3) and calcium oxide (CaO). The composition of common painted glasses is about 40–60% SiO2; they may also contain minor quantities of other oxides such as Al2O3 or B2O3. Most types of glass contain at least some fluoride salts as well as some boron oxide . Silicate glasses can be divided into two main groups: those with high viscosity and those with low viscosity.
Glass is used to make containers and fibers for textiles; it is also used in art objects and window panes. Glass can be colored by adding metallic compounds such as silver/copper salts or dyes/pigments which will create colored glass depending on the thickness of the applied layer
The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound silica (silicon dioxide, or quartz), the primary constituent of sand. Silicon is an element with a tetrahedral crystal structure (see silicon) while oxygen has a linear structure. The two atoms form a bond by sharing their electrons in covalent bonds. Typically, such shared pairs are arranged symmetrically between two oxygen atoms. In this arrangement each oxygen atom bonds with two silicon atoms and is thus bonded to four other molecules in total. This kind of network forms at temperatures above 1,300 degrees Celsius (2,372 Fahrenheit), therefore it is called vitreous (vitrification).
Glass is a solid that can be made into many shapes. It is a solid with a high index of refraction, which means it is transparent. Like other solids, it has a crystal structure and the chemical formula CaO•SiO2. Glasses are amorphous (non-crystalline) materials that are rigid at room temperature. The strength of glass depends on its composition: pure silica glass will shatter when struck with sufficient force, whereas borosilicate glasses will only crack or chip; soda lime glasses can be as strong as some stones. Pure silica glass has two types of bonds between its atoms: ionic bonds and covalent bonds; in ionic bonding electrons are shared between ions either evenly or unevenly, depending on whether they have an even or odd number of electrons respectively; in covalent bonding each atom shares valence electrons equally with all atoms bonded to it irrespective of their charges (it does not matter if one atom has more protons than another). This means that for every silicon atom there must be 4 oxygen atoms present for it to have no net charge (in this case Si+4= O-4+4).
Glass is used in many different ways. For example, it's used to make windows and bottles. It can also be used to make mirrors, art pieces and jewelry. Glass is also used for dishes and other kitchen tools. It's a very useful material that has been around for thousands of years!
There are some other things such as soda-lime glass, lead glass and borosilicate glass which is used in a lot of our daily life.