Volumetric expansion coefficients of simple materials are often well cataloged. However, the thermal expansion coefficient B of a human body is less well known. This could affect the human body's specific gravity and, therefore, measurements of its body‑fat ratio. Suppose that a human body of weight w0 on dry land is placed on a scale while completely immersed in formaldehyde of temperature T1. Once the temperature increases by ΔT, the scale reading drops by Δw. Derive an expression for B in terms of ΔT, w0, and Δw by assuming that the ratio of the density of formaldehyde pf and the initial density of the body pb is R=pf/pb. Assume also that pf does not change when heated.