Why does the speed of sound at high altitude decreases?

The speed varies depending on atmospheric conditions; the most important factor is the temperature. Humidity has little effect on the speed of sound, nor does air pressure by itself. Sound usually travels more slowly with greater altitude, due to reduced temperature.

How does air density affect speed of sound?

When the medium is dense, the molecules in the medium are closely packed, which means that the sound travels faster. Therefore, the speed of sound increases as the density of the medium increases.

What happens to the density of air as altitude decreases?

Altitude is height above sea level. The density of air decreases with height. There are two reasons: at higher altitudes, there is less air pushing down from above, and gravity is weaker farther from Earth’s center. So at higher altitudes, air molecules can spread out more, and air density decreases (Figure below).

Why is the speed of sound faster at sea level?

Air molecules at lower altitudes are closer together due to gravity, so the vibrations get transferred to the next air molecules faster, resulting in a faster speed at Low altitudes. Whereas in higher altitudes, air molecules are further from each other and the air pressure is lower.

Does the speed of sound change with altitude?

Since temperature (and thus the speed of sound) decreases with increasing altitude up to 11 km, sound is refracted upward, away from listeners on the ground, creating an acoustic shadow at some distance from the source. The decrease of the speed of sound with height is referred to as a negative sound speed gradient.

What are the factors that affect the speed of sound in gases?

Factors affecting speed of sound in gas, such as: Pressure, Density, Temperature, Humidity, frequency etc. P/ ρ = Constant. Therefore, with the change in pressure, the density also changes in such proportion, so that P/ ρ remains constant.

Why does density decrease with altitude?

The first reason is gravity. Earth’s gravity pulls air as close to the surface as possible. The second reason is density. As altitude increases, the amount of gas molecules in the air decreases—the air becomes less dense than air nearer to sea level.

Why does wind speed increase with altitude?

Going up in altitude, the pressure gradient between the warm air and the cold air increases with height. slow the air as it collides into them. The influence of this friction is less with height above the ground, thus the wind speed increases with height.

What happens to the speed of sound as the temperature decreases *?

Temperature is also a condition that affects the speed of sound. Molecules at higher temperatures have more energy, thus they can vibrate faster. Since the molecules vibrate faster, sound waves can travel more quickly. The speed of sound in room temperature air is 346 meters per second.

Does the sound travel faster or slower as temperature increases?

Therefore, sound travels faster at higher temperatures and slower at lower temperatures. Solids are much more elastic than liquids or gases, and allow sound waves to travel through them very quickly, at about 6000 feet per second.

How does the speed of sound change with increasing altitude?

With increasing altitude there is a decrease in the density but also a decrease in the pressure, but not at the same rate because there is also a change in the temperature. As the altitude increases, the temperature decreases and so does the speed of sound and then when the temperature increases so does the speed. Source – Engineering Toolbox

Why does the speed of a mechanical pulse decrease with altitude?

Analogously, if the density of the air is lower, the propagation of the mechanical pulse will take longer, that is, its speed will be lower. it has to do with the temperature lapse with altitude. since the speeed of sound is related to temperature by: and the temperature profile follows (generally) like the left of these three plots:

Why is the speed of sound lower at the Concorde’s cruising altitude?

At the cruise altitude of the Concorde the atmospheric temperature is below that of the standard atmospheric temperature at sea level, so the speed of sound is also lower. That is the simple answer.

How do airliners generate sound at low altitude?

The area of interest for airliners is in the lowermost region where the temperature is steadily decreasing with altitude (at a rate of ~6.5K/km) A sound wave moving through a gas requires a small scale bulk movement of gas molecules back and forth as pressure at any locations builds or falls.