As altitude increases, how does the speed of sound change?

As altitude increases, the speed of sound decreases primarily due to the decrease in temperature experienced at higher elevations in the atmosphere. Sound waves travel through the air as vibrations of air molecules, and the speed at which these vibrations occur is influenced by the temperature of the medium through which they are traveling.

At higher altitudes, particularly in the troposphere where the temperature generally decreases with altitude, the molecules move slower compared to lower altitudes. This reduction in molecular motion means that the sound waves propagate more slowly. While other factors such as atmospheric pressure can also impact the speed of sound, the primary factor at play in the context of increasing altitude is the drop in temperature.

Thus, the relationship between altitude and sound speed can be summarized: as altitude increases, the decrease in temperature leads to a decrease in the speed of sound.