The children entering their twelfth year begin to experience an important change in their physical bodies. Whereas before their movements were naturally graceful (generally speaking), now a certain clumsiness often appears, as if the children don't know quite what to do with their bodies. It is at this stage that concepts based on the laws of mechanics are introduced.
The Roman epoch epitomizes in an historical sense what the children are experiencing in their bodies. Of all the ancient peoples the Romans most strongly dominated the physical world. Their cities, roads, aqueducts, the Roman army, and their conquest of the Western world - all these accomplishments match a feeling of omnipotence that the sixth grader has: I can do anything! Yet equally important for the children is the example of how the excesses of the Roman period led to the eradication of native cultures, the fall of the Roman empire, and the Dark Ages.
With the children's increasing awareness of their physical bodies the time is right for the study of the physical body of the earth. Geology is introduced in a comparative way - the granite peaks of the Sierras may be contrasted with the worn limestone hills of the eastern United States.
Children are also introduced to the basic concepts of physics. As with all the subjects in our school, the approach to physics is first through art: acoustics comes through observing how music is made; the children discover that they too have a musical instrument within them, the larynx. Optics is introduced through contemplating the qualities of color.
Whereas geometric shapes have in the prior grades been drawn freehand as artistic exercises, the sixth grader learns the mathematical properties of these forms and strives to construct them with great accuracy using ruler and compass.