A backpacking stove manufacturer is deciding between two metals for a new lightweight…

PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter

Problem

A backpacking stove manufacturer is deciding between two metals for a new lightweight cooking pot. Relevant measured properties for the two candidate metals are provided below. Material Data (at room temperature) • Aluminum alloy: specific heat

c = 900\,\text{J\,kg}^{-1}\,\text{K}^{-1}

, thermal conductivity

k = 210\,\text{W\,m}^{-1}\,\text{K}^{-1}

, density

\rho = 2.7\,\text{g\,cm}^{-3}

• Cast iron: specific heat

c = 460\,\text{J\,kg}^{-1}\,\text{K}^{-1}

, thermal conductivity

k = 80\,\text{W\,m}^{-1}\,\text{K}^{-1}

, density

\rho = 7.2\,\text{g\,cm}^{-3}

Assume each pot has the same wall thickness and interior volume. (a) Describe what is meant by an "intrinsic property" of a material. Explain why both specific heat and thermal conductivity are classified as intrinsic. (b) For the purpose of quickly boiling water on a camp stove, discuss how the relative magnitudes of

c

and

k

for the two metals influence (i) the time required for the pot itself to reach the water’s temperature and (ii) the efficiency with which thermal energy from the flame is delivered to the water. (c) Using only the data provided, justify which metal you would recommend for the backpacking pot. Your argument should explicitly weigh thermal performance against the practical considerations of mass that a hiker must carry.

Related theory

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