What happens to pressure as altitude increases?

As altitude increases, atmospheric pressure decreases. This phenomenon occurs due to the weight of the air above a given point on the Earth's surface. At higher altitudes, there is less air above to exert pressure because the air density decreases.

In simple terms, as you ascend into the atmosphere, the amount of air (and thus its weight) above you becomes less, resulting in a drop in pressure. This principle is fundamental in various applications, including aviation, where understanding pressure changes with altitude is crucial for flight safety and performance.

While some options may imply alternate scenarios—like pressure increasing or remaining constant—those do not align with the established scientific understanding of atmospheric behavior. The fluctuation of pressure could occur locally due to weather changes, but the overall trend with altitude is a consistent decrease in atmospheric pressure. Thus, as one rises in altitude, they will experience a decrease in pressure, making the correct answer clear.