A Simple Experimental Procedure for the Approximate Determination of the Heat Capacity of Metals in a Natural Convection Environment under the Premises of a Lumped Model

Abstract

A method is presented of measuring the specific heat capacity, Cp, of pure metals and alloys in an undergraduate thermofluids laboratory using simple concepts of unsteady heat conduction in solids and natural convection in fluids taken from textbooks on heat transfer. A simple experiment was developed in which a small-diameter metallic sphere at ambient temperature (∼20° C) is suddenly immersed in a tank containing quiescent ice water at 0° C. The metallic sphere was suspended by the lead wire of a thermocouple and the temperature-time evolution was recorded. A first-order differential equation descriptive of a lumped model was used. Although the equation is nonlinear, a variable transformation converted it into the Bernoulli form, which allows an analytic solution. Introduction of two measured temperatures at two distinct times into the analytic solution allows the specific heat capacity of a metallic material to be determined by means of an algebraic procedure.