Yes, sound does tend to travel slower through thinner air. The speed of sound is influenced by various factors, including the density, temperature, and humidity of the medium through which it propagates.
In general, as the density of a medium decreases, such as in thinner air at higher altitudes, the speed of sound decreases. This is because sound waves rely on the collisions between molecules to propagate, and with fewer molecules per unit volume, there are fewer collisions, leading to a slower speed of sound.
In addition to density, temperature also plays a significant role in the speed of sound. In general, as the temperature of a gas increases, the speed of sound within that gas also increases. This is because higher temperatures lead to increased molecular motion and faster collisions between molecules, facilitating the propagation of sound waves.
Therefore, in thinner air at higher altitudes, where both density and temperature tend to decrease, sound waves will typically travel more slowly compared to denser air at lower altitudes. However, it's important to note that other factors, such as humidity and composition of the air, can also influence the speed of sound to a lesser extent.