How is and what material is used to make 'Glass'?

You can find a discussion of glass batch and making glass from sand (mostly), soda ash to lower melting point, and limestone (calcium carbonate) to make it more durable plus other bits to do other details here: http://users.ticnet.com/mikefirth/batch.htm In large production situations, glass is melted in huge tanks where flame (usually gas) surrounds the tank. In most commercial setups, the exhaust fumes are taken out through a large array of fire brick, laid loosely. After a while, the air flow is reversed so that in the incoming air is heated from the hot brick, saving fuel for just heating the air and the exhaust goes out through another set. This is called recuperative heating. In the tank, batch mix is dumped in one end which is kept hotter and as the batch melts, the liquid passes under a barrier that blocks the crud. The main holding tank remains at a constant level for processing efficiency and the process is called continuous melt. Depending on what is being made, either the molten glass is tapped in a stream that is fed to molds or it is drawn in some manner to make sheet. When it is done with molds, a glop (my term) dropped into a cup at the top of the mold and then a "mouthpiece" is pushed into the cup and air blows the glass down into the mold, filling it out. In the glassware line I saw at Libby Glass, the top of the mold then splints and moves away and a sharp hot flame cuts a line so the upper blowing cup is pulled away and the glassware is released when the lower mold splits and sets the glassware on a conveyor that goes through a lehr which anneals the glass (cools it relatively slowly). Bottles are done roughly the same way. The molds and blowing hardware are mounted on a merry-go-round looking thing - about 16 sets so it turns under the glass stream, then around as other steps happens, then cooled somewhat and all over again. Window glass is made these days by pulling a flat sheet straight up and then bending it over and lying it on molten tin in a nitrogen atmosphere a process developed by Pilkington http://www.pilkington.com/ in the 1950's. Called float glass it results in perfectly flat glass sheet with no ripples as produced by earlier methods. Stained glass is made by a variety of methods including pouring a ladle of molten glass on a table and rolling a heavy roller over it and blowing a long cylinder and cutting it open be sagged flat. Some is made by overflowing a tank in a flat stream and pulling the sheet horizontally and stretching it into a lehr where it is trimmed and cut to size as it comes out the other end.

limestone sand and sodium bicarbonate

Limestone is heated with pure sand (silicon dioxide)

gets heated up to molten heat and when it cools it dosnt turn to sand it turns to ice instead x