First Law of Thermodynamics

What is First Law of Thermodynamics?

Energy can neither be created nor destroyed, only converted between forms — heat added to a system minus work done by it equals the change in its internal energy. It's the same conservation-of-energy principle from mechanics, simply extended to account for heat as well as work.

The five clues

Engineerdle #4 described First Law of Thermodynamics with five clues, revealed one at a time from hardest to most direct. Each clue points at a different property of the concept.

1. 01It's really just an old idea from mechanics, dressed up for heat and work.
2. 02Energy entering a system has to show up somewhere.
3. 03It can change form, but the books must always balance.
4. 04Add heat, do work, and internal energy is whatever's left over.
5. 05ΔU = Q − W.

More Thermodynamics concepts

• Triple PointPuzzle #52
• Isentropic ProcessPuzzle #44
• EntropyPuzzle #39
• Adiabatic ProcessPuzzle #34
• Latent HeatPuzzle #14
• Specific Heat CapacityPuzzle #9