Did you ever consider how glass was discovered? I'm sure you have thought about it. It's such an important product in our generation; without it the world would be cold or hot and, surely, dark.
Did you know that glass is found in nature? Every time hot lava from a volcano touches sand or a sand-based rock, glass is formed. Whenever a lightning strike hits sand or a sand-based rock, glass is formed. Of course, someone, many centuries ago, put two and two together and figured there must be a connection here. Since people were long ago into pottery glazing and metalworking done in kilns, they must have theorized that they could make glass in the same fire.
The very first glass products date to 2,500 years before Jesus was born. Vessels of various types to hold liquids. The first glass objects made thin with a glassblower date to 1 BC. Some people made use of naturally formed glass for windows about 100 AD. They weren't much to look through but they were better than the oil skins they had used to cover the openings in buildings. Clear thin glass continued to develope into the middle ages when it was used in churches and the homes of the very wealthy.
Windows of glass finally started to be used in homes of the middle class in the 1600s. In addition, stained glass windows were developed during this period.
Perfectly clear, distortion-free windows didn't exist until after World War II. That means that when my father first got a look at me through the window in the hospital nursery, I may have looked slightly odd to him. Then again, to this day, I may look slightly odd to you.