Question

Hw is a glass made ?

Answer 1

 glass is made from liquid sand. You can make glass by heating ordinary sand (which is mostly made of silicon dioxide) until it melts and turns into a liquid. You won't find that happening on your local beach: sand melts at the incredibly high temperature of 1700°C (3090°F).

Answer 2

Glass is formed when sand or rocks, often high in silica, are heated to high temperatures and then cooled rapidly. 

First sand is heated as to a extreme temperature and then it is cooled down slowly .