Things You'll Need
Clay shaping tools, such as scalpel, straight edge and pens
The human skull has a very unique shape. You can make a replica of one from clay by paying careful attention to a few key areas, which are defined by distinct contours. Whether it's for your science class or a Halloween party, it's possible to achieve an accurate finished product without too much time or effort.
Create a sphere with some polymer clay. The amount of clay will depend on how large or small you want the clay skull to be. Roll the clay in your hands until you have formed a smooth ball.
Roll the sphere in your hands, concentrating a little more on one end to create an egg like shape. Point the smaller tip of the "egg" towards you and press two indentations on each side to create the cheek area.
Press the rounded area in between the indentations flat. This will be the area where the teeth and nasal openings will be added. Turn the skull to the side and use a straight edge to create a flat "ledge" where the jaw area and the rounded back part of the skull meet.
Use a clay carving tool to gently score the outline of the teeth over the lower half of the flat area between the cheek indentations. There are two ways to execute the teeth: outlining each tooth separately to form two rows or simply create a strong line across the mouth and using a scoring tool to make vertical lines across it.
Add the nasal opening just above the teeth. It looks like an upside down V.
Use a tool with a rounded end to press the clay in circle-shaped indentations where the eyes would go. Depending on how large or tiny your skull is, this tool could be anything from the end of a ballpoint pen to the end of a rolling pin. Smooth the indentations with your fingers so that the sockets look natural to the shape and not forced, especially around the edges.
Smooth out polymer clay by gently rubbing a smoothing oil over it with a soft brush.
Make the skull more cartoon-like by adding eyeballs, an exaggerated chin, and a smirking grin.
For permanence, fire the skull in a kiln once you are finished sculpting it.
If you want the skull to resemble an archeological find, try breaking off part of the jaw or making a big hole in the top.