[eli5] How does an altimeter work? How does it know how high you are off the ground?

Question

[eli5] How does an altimeter work? How does it know how high you are off the ground?

In: 69

Answer 1

*An altimeter is a device that measures altitude—a location’s distance above sea level. Most altimeters are barometric, meaning they measure altitude by calculating the location’s air pressure. Air pressure decreases as altitude increases.* [Source](https://education.nationalgeographic.org/resource/altimeter)