Matter (Eyewitness Science)

On a certain page of "Matter" a callout next to a picture of a glass lens states that "glass flows over time". This is a widely believed myth that is simply not true. The "evidence" for the liquid nature of glass comes from old church and cathedral windows that appear to be thicker at the bottom as the glass has flowed over the centuries. This is not the case. Here is why they are thicker at the bottom: "In Mediaeval times panes of glass were often made by the Crown glass process. A lump of molten glass was rolled, blown, expanded, flattened and finally spun into a disc before being cut into panes. The sheets were thicker towards the edge of the disc and were usually installed with the heavier side at the bottom." Examples of other pieces of ancient glassware (Roman, etc.) exhibit no signs of glass "flow".

"Eyewitness Matter" tells everything about Matter. It has chapters on solid matter, liquid matter and gas matter, plus chapters on molecules in motion, crystals, hot matter and more! All of the chapters in the book have descriptive information on the topics in Matter. If you have gotten the other Eyewitness Science Series books, then make sure you have this one.