Model of a Thermodynamic Surface by Richard P. Baker, Perfect Gas, Baker #221

This is a model of a thermodynamic surface, representing the behavior of a perfect gas. A square wooden base supports a sloping wire grid structure. Thinking algebraically, the equation for the expansion of a perfect gas is PV = kT, where P is pressure, V is volume, T is temperature, and k is a constant. On the surface, temperature increases as one moves vertically (the black wire in the corner of the model represents increasing temperature). The origin of the coordinate system describing the gas is on the corner of the base diametrically opposite this wire. Pressure increases going toward the back, with white wires on the surface representing equal pressures. Volume increases going to the right, with red wires representing equal volumes. Blue wires represent lines along which the temperature is constant (isotherms). Yellow wires represent lines of constant entropy (adiabats).

A tag on the bottom of the model reads: No. 221 (/) Perfect gas.

For more information about thermodynamic surfaces, see MA.211257.045.

Reference:

R. P. Baker, Mathematical Models, Iowa City, Iowa, 1931, p. 18.

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