Glass is not a liquid or a solid — it is a 'frozen' liquid that stays still forever.

Glass is what scientists call an amorphous solid. When glass is made, hot liquid is cooled down so fast that the atoms do not have time to line up in a neat pattern. Instead, they get stuck in a messy, jumbled pile. This makes glass look like a solid, but its atoms are arranged like a liquid that is frozen in place.The idea that glass flows comes from looking at very old houses. In the 1700s and 1800s, glassmakers made windows by spinning molten glass into a big flat circle. This process made the edges of the glass thicker than the center. When builders put these windows into houses, they usually put the thick side at the bottom to make the window more stable.In 1998, a researcher named Edgar Dutra Zanotto studied how thick glass really is. He published his work in the American Journal of Physics. He calculated that for a piece of glass to flow even a tiny amount at room temperature, it would take 10 to the power of 32 years. That is a number followed by 32 zeros!To put that in perspective, our entire universe is only about 13.8 billion years old. Glass would need way more time than the age of the universe just to sag a little bit. Today, we use the float glass process invented by Alastair Pilkington in 1952. This method floats hot glass on top of melted tin to make it perfectly flat and even every time.