(6)In each case the crystals,small orlarge,are naturally bounded by square or rectangular crystal faces of different sizes,but with each face always at right angles to each adjacent face.
(2)In simple harmonic motion,where there is no damping,the energy of the vibrating particle changes from kinetic to potential and back,with the total energy constant.
(3) An uncharged object contains a large number of atoms, each of which normally contains an equal number of electrons and protons,but with some electrons temporarily free from atoms.