Definition
A physical law combining Boyle's Law and Charles's Law into a single relationship that describes how the pressure, volume, and absolute temperature of a fixed mass of gas relate to one another. It is commonly stated as P1V1/T1 = P2V2/T2, meaning that for a given amount of gas, the ratio of pressure times volume to absolute temperature stays constant as conditions change.
Plain English
A rule that ties together a gas's pressure, volume, and temperature. If you change one, the other two adjust in a predictable way.
Context Anchor
Seen in aircraft systems, weather, and performance discussions where air pressure, air temperature, and air volume are connected.
Derivation
General' here means it covers the general case — combining the earlier, more limited gas laws (Boyle's, which holds temperature steady, and Charles's, which holds pressure steady) into one rule that handles all three variables changing at once.
Why Pilots Care
It explains how air density changes with altitude and temperature, directly affecting lift, engine power, and altimeter accuracy.
Analogy
A sealed balloon is a simple picture of the idea. Warm it, cool it, or squeeze it, and the pressure and size of the air inside respond together.
Grounding Statement
Squeeze a gas into a smaller space and its pressure rises; warm it up and either its pressure or its volume must increase. The General Gas Law puts numbers to that everyday behavior.
Intuition Check
“Law” here does not mean an FAA regulation. It means a predictable physical rule for how gases behave.
Example Sentence 1
Using the General Gas Law, the technician calculated how much the oxygen bottle pressure would drop after the aircraft cooled overnight on the ramp.
Example Sentence 2
Pilots use the general gas law when calculating how high temperatures reduce air density and engine performance.