What happens to air pressure as altitude increases?

As altitude increases, air pressure decreases due to the decreasing density of air with height. This phenomenon is mainly due to the weight of the air above exerting pressure. At higher altitudes, there are fewer air molecules above a given point, which translates to lower pressure.

The relationship between altitude and air pressure can be attributed to the ideal gas law, which indicates that as the volume of gas (in this case, the atmosphere) increases, the pressure decreases if the temperature remains constant. Therefore, as one ascends, air becomes less dense, leading to a reduction in air pressure.

This principle is critical for pilots, as they must understand how altitude affects aircraft performance and engine operation. At higher altitudes, the decrease in air pressure also influences lift, control surfaces, and engine efficiency, making this concept key in aviation operations.