Water forms phases of XI, Ic, Ih, Quasisolid (QS), Liquid, and vapors associated with density oscillation when heated under the ambient pressure, which has been long standing puzzle sing 1611 when Galilei argued that ice floating results from density change. The HBCP premise allows us to solve this issue by introducing the segmental specific heat of Debye approximation. The specific heat depends on two factors: one is the cohesive energy E that equals the integral of the specific heat curve, and the other Deby temperature following Einstein relation, ΘD ∝ ω. With known (ω, E)x, one could readily define the specific heat ηx. The segmental disparity defines two specific heat curves and hence the phase boundaries and mass density variation with temperature . )