energy contained in a system, excluding energy due to its position as a body in external force fields or its overall motion
Internal energy is the total energy stored inside a system from the motion and interactions of its particles, not counting the energy from where the system sits or how fast it's moving as a whole. It matters because understanding what energy is actually available inside a system helps us predict how it will behave when it heats up, cools down, or undergoes chemical changes.
AI-generated from the Wikipedia summary — may contain errors.
System properties
Note: Conjugate variables in italics
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).