Although modern sculptors employ a wide range of methods and
an expansive variety of artistic techniques in the creation of a
piece, classical sculpture was limited for the most part to two
basic types, carving and casting. 

     Carving begins with a large piece of material such as stone,
ivory, or wood. The artist, using a hammer and chisel, a knife, 
or even sandpaper, then begins the process of reducing it1 down 
to the shape or form desired. Thus, carving is essentially a 
process of removal and, as such, is limited by the size and 
physical properties inherent in the material to be carved. 
Further, because large blocks of marble, for example, are 
extremely expensive, it is imperative that the sculptor both 
understand the characteristics of the medium and work first with
scale models of the piece to be produced. One of the most famous
sculptures produced by carving is Michelangelo's David, an 
invaluable piece, created over a three-year period of time, that
seems to bring life to the marble in which it2 was carved.

     Casting involves a completely different process. In casting
, the artist first produces a model of the piece to be created 
out of clay or some other easy-to-manipulate substance. 
Plaster--a liquid made of lime, sand, and water that hardens 
over time-- is then used to make a mold around the model. The 
mold conforms to the shape of the clay model, hardens, and is 
then opened (or carefully split into two pieces) for the removal
of the clay model. The mold is now ready to be used for casting.
In the casting step, the mold is reassembled, and plaster, 
bronze, or some other material is poured inside through a small
hole. Once the material inside hardens, the mold is shattered or
chipped away, leaving a cast of the original clay model, which 
can then be painted or adorned as the artist pleases. The 
Burgher of Calais, a bronze statue by Rodin commemorating an 
important event in French history, is a fine example of the work
that can be created using this method.