Sharing Energy

Equipartition and heat capacity

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Equipartition: each quadratic degree of freedom averages $\tfrac12 k_B T$.
• A monatomic gas atom has average kinetic energy $\tfrac32 k_B T$.
• Quantised motions with large energy steps are “frozen out” at low temperature.

Steps

1. Fair shares
2. Average energy
3. Heat capacity of a gas
4. Hydrogen’s staircase
5. Energy in a mole of air
6. A quantum surprise