How do you make glass? – Manganese Zone

Question: How do you make glass?
- Keywords:
  glass
Asked by cateliin3 to David, Rebecca, Simon, Verity, Wei on 16 Jun 2011.
- Verity Nye answered on 16 Jun 2011:
  
  By melting together a combination of sand and other minerals at very high temperatures.
- Wei Xun answered on 16 Jun 2011:
  
  I think David might be the best person to answer.
  
  I know that glass is made up of mostly sillica and it’s not strictly a solid, but some kind of weird liquid that never quite sets, is that true David?
- David Armstrong answered on 16 Jun 2011:
  
  Glass is an amorphous solid – this means the atoms are all randomly arranged (in most materials the atoms are arranged in regular arrays). Glass is made from silica (sand) and different amounts of additives depending on what properties you want the glass to have. These are melted together and then cast onto a bed of liquid metal. This ensures that the glass is perfectly smooth – this proces is called the float glass process.
  
  Before this was developed, glass for windows was made by heating it up and spinning it on a plate until it stretched out. This left it thicker in the middle than the edge. When it was then cut into window planes the glazer would balance it on the thicker end. That’s where the myth that glass is liquid comes from – it doesn’t really flow down over time.

Question: How do you make glass?