In homeschool science, we are learning more about the skeletal system. Here is an experiment that my son did:
Shape a human (or other creature) from a lump of clay. Give it long, thin legs and arms; put a head on it's shoulders. Go ahead and squish the head flat because that's what your head would look like if you did not have a skull. (My son didn't want to smash his creature.) Now see if the figure can stand up on its own. If you made your figure correctly, it will not be able to stand.