---
tags:
  - science/physics
  - laws
  - conservation
  - symmetry
created: 2026-05-16
breadcrumb: "Physics > Laws of physics > Conservation laws"
---

# Conservation laws

> **Mechanism:** Symmetries → conserved quantities (Noether)

## Items

- **Energy** — Total energy of a closed system is constant. Cannot be created or destroyed — only transformed.
- **Linear momentum** — Total momentum of a closed system is constant. Translation symmetry.
- **Angular momentum** — Total angular momentum is constant in isolation. Rotational symmetry.
- **Electric charge** — Net electric charge cannot be created or destroyed.
- **Baryon / lepton number** — Approximate conservation laws in particle physics.

## Related

- [[newtons-laws]]
- [[thermodynamics]]