As we have seen from our laboratory study and modeling of crystals and crystal shapes, the regular and predictable spatial arrangement of (external) crystal faces is a direct reflection and outgrowth of the orderly and patterned internal arrangement of its atoms and molecules. Careful study of crystal shapes and their respective geometries provide valuable clues into the molecular infrastructure and architecture of the matter of which they are comprised. However, crystals and objects comprised of crystalline matter are not the only objects which seek or follow a symmetrical plan of arrangement. There is scarcely any object in our everyday world, both natural and synthetic (man-made), which does not possess some expression of symmetry.
The following is a list of common objects to which you all have access. Find examples of them either in your house, yard, street or general neighborhood and describe the symmetry elements present (if any). As you may recall, the three symmetry elements are the plane (mirror), the line (rotational axis) and the point (inversion). Study each object carefully and fully, observing it from all perspectives and views. On the line adjacent to the object, list the element(s) present and the reason why. Some objects may possess more than one symmetry element. List all that you have discovered and explain.