2.  A physical property describes the substance without reference to any other substance.  Weight  Volume  Color  Boiling Point  Melting Point  A chemical property describes the behavior in relation to another substance.

3.  It can be lodged in a suspects shoes or clothes.  Headlight glass can help identify a suspect’s vehicle.

4.  Glass is made of silicon oxide and metal oxides.  Sand and metal oxides are melted and then cooled.

5.  Window and bottle glass are made of soda- lime, sand and metal oxides.  Auto headlights and heat-resistant glass also have boron oxide.  Tempered glass is stressed glass that is rapidly heated and cooled.  Laminated glass is used as windshields and is made by sandwiching a piece of plastic between two pieces of window glass.

6.  Pieces are put together like a puzzle.  Refractive index: velocity of light in a vacuum divided by the velocity of light in the medium.  Density: the mass divided by the volume.