---
title: "Isolated System — AP Physics 1 Definition & Exam Guide"
description: "An isolated system exchanges no matter or energy with its surroundings, so momentum and energy are conserved. Key to Unit 4 collisions and explosions on AP Physics 1."
canonical: "https://fiveable.me/ap-physics-1-revised/key-terms/isolated-system"
type: "key-term"
subject: "AP Physics 1"
---

# Isolated System — AP Physics 1 Definition & Exam Guide

## Definition

An isolated system refers to a physical system that does not exchange matter or energy with its surroundings.

## Related Study Guides

- [Unit 5 Overview: Momentum](/ap-physics-1-revised/unit-qDcgBEsIVe7Ydnh4/review/study-guide/oD1HKk5HsSpc6zw7VaMW)
- [4.1 Open and Closed Systems: Energy](/ap-physics-1-revised/unit-4/open-closed-systems-energy/study-guide/osnnllT8innOlpvGmXFK)

## Review

### Related Terms

- Adiabatic Process: A process where there is no transfer of heat between a system and its surroundings.
- Entropy: A measure of the disorder or randomness in a system. In an isolated system, entropy tends to increase over time.
- Laws of Thermodynamics: Fundamental principles governing the behavior of energy in various systems, including isolated systems.