Student handout: Ideal Gas Model

Students consider whether the thermo surfaces reflect the properties of an ideal gas.
  • group Small Group Activity schedule 30 min. build Ideal Gas Contour Maps, handout for each student, purple and blue thermo surfaces for instructor, personal or shared writing space for each student description Student handout (PDF)
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    Ideal Gas surfaces thermo
What students learn
  • Equation and definition of an Ideal Gas
  • Students explore what it would mean for something to be an ideal gas or a good approximation of an ideal gas
  • Students might discuss the difference between temperature and internal energy
  • Can discuss degrees of freedom

The internal energy of an ideal gas is described by the equation:

\[ U(p,T)=\left(\frac{\# dof}{2}\right) NkT \]

The surfaces represent the internal energy of water vapor:

  • The blue surface shows the internal energy as a function of temperature and pressure, \(U(T,p)\), with volume and entropy contours etched into the surface.
  • The purple surface shows the internal energy as a function of volume and entropy, \(U(S,V)\), with pressure and temperatures contours etched into the surface.

By examining the plastic surfaces, how can you tell if an ideal gas model is a good model for water vapor?

Author Information
Raising Physics to the Surface
Ideal Gas surfaces thermo
Learning Outcomes