Human bones are dynamic tissues that are remodeled constantly through processes that remove existing bone and deposit new bone. We aim to create more informative--and ultimately more medically useful--models of bone dynamics by developing a three level approach. The first is the microscopic level that incorporates the bone cells and signaling molecules, coupled to external mechanical stimulus. The second is the intermediate level that examines the effects of remodeling on the individual beams of spongy bone. The third is the macroscopic level of the whole bones in terms of how bone structure change affect bone's mechanical properties. My current focus is the first level modeling using a set of continuous equations to investigate how mechanical stress/strain could influence the average bone porosity.