what properties do both glass and plastic share that allow them to be substituted for each other in some applications? what properties do glass and plastic have that make them quite different?
difficult stuff. seek with bing and yahoo. just that can help!
I don't believe that to be true
Some similarities (there are many): 1. Moldability. Glass and many plastics (thermoplastics) can be melted and formed into a desired shape. 2. Optically transparent. Glass and many plastics are transparent - this is because they are amorphous and do not form crystal-crystal interfaces that reflect light (making them opaque). 3. Cheap - most types of glass and most plastics are pretty inexpensive. They are made from cheap starting materials like sand and natural gas. 4. Recyclable. The materials used to make glass and most plastics are cheap - a lot of the cost comes from the energy required for the production process (especially for glass). Recycling allows both raw materials and significant energy to be saved. Differences (again, only a few of many): 1. Chemical reactivity. Most glasses are very resistant to chemical attack and can be used to handle chemicals. Glass also resists weathering better than most plastics do. 2. (A subset of the previous difference) Flammability. Most organic polymers burn in air, glass does not. Thus, glass wool can be woven into fire-resistant fabrics, but synthetic fabrics like nylon will melt and burn in a fire. 3. Thermal resistance. While both glass and many plastics can melt, most plastics melt and/or decompose at much lower temperatures than glass melts at. 4. Density. Glass tends to be denser than plastics - when it is important to conserve weight, plastics are a better choice.
