The equivalence principle in the Schwarzschild geometry, William Moreau, Richard Neutze and D.K. Ross, Am. J. Phys. 62(11), November 1994
Written in its standard form the Schwarzschild line element obscures the equivalence principle which is hidden in its geometrical structure. Through a coordinate transformation we re-express the line element in a form composed of terms of two types: (1) terms that correspond to a line element in a uniformly accelerated reference frame in flat space-time, and (2) terms that correspond to curvature and are related to geodesic deviation. The dissection of the Schwarzschild line element into two parts, one corresponding to acceleration and the other to curvature, provides a good specific example of Einstein's equivalence principle.