Would windows in a castle around 40 A.C.E. have glass?
461108
100 A.D.\nThe Roman connection\nThe Romans also did much to spread glassmaking technology. With its conquests, trade relations, road building, and effective political and economical administration, the Roman Empire created the conditions for the flourishing of glassworks across western Europe and the Mediterranean. During the reign of the emperor Augustus, glass objects began to appear throughout Italy, in France, Germany and Switzerland. Roman glass has even been found as far afield as China, shipped there along the silk routes.\n\nIt was the Romans who began to use glass for architectural purposes, with the discovery of clear glass (through the introduction of manganese oxide) in Alexandria around AD 100. Cast glass windows, albeit with poor optical qualities, thus began to appear in the most important buildings in Rome and the most luxurious villas of Herculaneum and Pompeii.\n\nWith the geographical division of the empires, glass craftsmen began to migrate less, and eastern and western glassware gradually acquired more distinct characteristics. Alexandria remained the most important glassmaking area in the East, producing luxury glass items mainly for export. The world famous Portland Vase is perhaps the finest known example of Alexandrian skills. In Rome's Western empire, the city of Köln in the Rhineland developed as the hub of the glassmaking industry, adopting, however, mainly eastern techniques. Then, the decline of the Roman Empire and culture slowed progress in the field of glassmaking techniques, particularly through the 5th century. Germanic glassware became less ornate, with craftsmen abandoning or not developing the decorating skills they had acquired.\n\n11th century\nSheet glass skills\nThe 11th century also saw the development by German glass craftsmen of a technique - then further developed by Venetian craftsmen in the 13th century - for the production of glass sheets. By blowing a hollow glass sphere and swinging it vertically, gravity would pull the glass into a cylindrical "pod" measuring as much as 3 metres long, with a width of up to 45 cm. While still hot, the ends of the pod were cut off and the resulting cylinder cut lengthways and laid flat. Other types of sheet glass included crown glass (also known as "bullions"), relatively common across western Europe. With this technique, a glass ball was blown and then opened outwards on the opposite side to the pipe. Spinning the semi-molten ball then caused it to flatten and increase in size, but only up to a limited diameter. The panes thus created would then be joined with lead strips and pieced together to create windows. Glazing remained, however, a great luxury up to the late Middle Ages, with royal palaces and churches the most likely buildings to have glass windows. Stained glass windows reached their peak as the Middle Ages drew to a close, with an increasing number of public buildings, inns and the homes of the wealthy fitted with clear or coloured glass decorated with historical scenes and coats of arms.\n\n\nPossibly, but high quality didn't emerge until 1,000 years later.
567582
Mine is the kind that has walls, windows and a roof.\n\nAlmost forgot, it has doors too.
338497
Not as much as sitting outdoors. The glass shields some of the UV rays.
29825
I visited Corning Glass at Elmira, NY, home of Steuben Glass.  I believe I learned there (or read it?) that it is easier to make glass by adding sand to molten glass to dissolve the sand than to melt raw sand.  For that reason recycling used glass bottles etc, actually helps the glass industry.  Of course there are many types of glass.  For example, I believe that leaded glass can contain perhaps 40% lead and is crystal clear and easier to etch or cut.  Most common glass is soda glass and can dissolve in water over time.  Antique bottles found in old household dumps are often pitted from groundwater.
106734
It depends on the relative humidity. The location with more relative humidity will cause more "sweating" or condensation on the outside of the glass. \n\nThis will usually be indoors, since it is usually drier indoors, thanks to air conditioners in the summer, and heaters in the winter.
969632
Yes, Glass should be the cheapest product you should buy. It is made of Silicate which is sand. They heat the the sand up using special vessels to remove any impurities from the Silicate, then the glass is formed at a different temperature after removing all impurities from the sand.
473094
Glass is more dimensionally stable - it doesn't expand or contract when the temperature changes - and it can be polished to a very smooth surface.   The finish is a very very thin layer of metal.\n\nRead "The Perfect Machine" by Ronald Florence if you want to learn more.
672330
Glass is made from silica and sand, heated at very high temperatures.  Different colors come from adding different metals and other elements.
1009573
go look outside windows
777660
Nah, I'd go for...\n\n"Why do we keep our windows closed when it's cold outside?"
372151
If you tint it, it adds to the heat being absorbed to the glass.  Dark things absorb more light, light colors reflect more.  So the window should then start becoming hotter than before and hence why you should start seeing it crack now.  Also is the window facing east, it would explain the time of day it is cracking.  Now the window will not only heat to a high temperature, it will do it faster from the however cold it will have gotten overnight.
352065
some is reflected by the glass, and some passes straight through.  A tiny part will go towards heating up the glass itself, as it is absorbed during its transition throught the glass.
480536
should be glass. unless in its original form of sand than should be water. Remember Super-man made that huge piece of glass to reflect the sun an blind those crazy alien people!
646733
glass has the property to transmit light from one side to the other side of it. other objects stop the light..or atleast do not pass the light fully.. thats why glass is tranparent to the other side
1115641
If it hits sand, it will often make glass.  It makes the ground very hot for a short time, having so much moisture around it draws the heat away quickly.
1173893
How about glass, plastic, stone, metal, ...?
866604
They aren't.\n\nOval windows solve stress fracture problems.