[Verse 1] Thermal energy splits in parts Each quadratic term gets its share Write the Hamiltonian, count them out Every term contributes there [Chorus] Half k T, half k T Each degree of freedom gets Half k T, half k T Add them up, that is your U [Verse 2] Three for motion, x y z Translation in free space Linear molecules rotate in two Nonlinear takes three in place [Chorus] Half k T, half k T Each degree of freedom gets Half k T, half k T Add them up, that is your U [Bridge] Translation always counts Rotation often joins it too Vibration stays quantum-frozen Until T is high enough [Final Chorus] Half k T, half k T Each degree of freedom gets Half k T, half k T Add them up, that is your U