How is glass made?

The process that turns sand into glass is very cool – or rather, we should say very hot. Very, very, very hot as it turns out. Humans have been turning minerals from the earth’s crust into glass for 3,500 years. Find out how it’s done and how it’s evolved – from blowing glass by hand to a factory that makes hundreds of glass bottles every minute. Plus: The mystery sound! See omnystudio.com/listener for privacy information.