Fuel Energy, Work of Gas and Vapor, and Heat Engines
How the chemical energy locked inside fuel is turned into motion
Big Idea: When a fuel burns, energy that was stored in it is released as heat. If we let the hot gas or steam expand and push a piston, that heat becomes useful mechanical work. A machine built to do this over and over is a heat engine — the engine in a car, bus, or ship.
By the end you will be able to:
- use the specific heat of combustion q and the formula Q = qm;
- explain how an expanding gas or vapor does work and why it cools;
- name the three essential parts of every heat engine and the main kinds;
- calculate efficiency with η = A/Q1, and say why it is always below 100%;
- describe how heat engines affect the environment.