Why is the speed of sound related to temperature?

Why is the speed of sound propagation related to temperature? Why?

The speed of sound is related to temperature. Generally speaking, the speed of sound will increase with the increase of temperature.

In air, within the range of perennial temperature change, the speed of sound increases by about 0.6 m/s every time the temperature rises by one degree.

v = v0 + 0.6t

Where v0 = 33 1m/s is the speed of sound at 0℃ in air.

The above formula is called empirical formula.

Why does the higher the temperature, the greater the speed of sound?

Research shows that the speed of sound propagation is directly proportional to temperature, so the higher the temperature, the greater the speed of sound.

Generally speaking, the propagation speed of sound is only related to the medium, and the propagation speed of the same medium will be somewhat different under different conditions, but these are the results of scientific research and there is no need to study them in detail. Here are some details about the relationship between sound and temperature.

Sound is energy transmitted in the form of sound waves. Generally speaking, when sound travels far or slowly, it will consume a lot of energy. If all the energy of sound waves is consumed on the way or the sound waves change direction, people's ears will not hear the sound. The speed of sound propagation is closely related to the types and conditions of elastic media. Generally speaking, the speed of sound is 340 meters per second, and the propagation medium is 15℃ standard air. In fact, it is impossible for the air around us to "reach the standard", and its situation is closely related to the combination of various meteorological elements (that is, weather conditions).

Research shows that the speed of sound propagation is directly proportional to temperature. In the near-surface layer, when the temperature decreases with the elevation, the propagation speed of sound decreases with the elevation, and the sound line will bend upward (commonly known as "acoustic takeoff"). On the contrary, when the temperature increases with the increase of height, the speed of sound propagation will increase with the increase of height, and the sound line will bend downward, giving people the sense of hearing that "the sound is sinking".

On rainy days, the temperature is relatively low. The closer to the ground, the higher the air temperature, and the rays of sound bend into the air, so it is not easy for people on the ground to hear distant sounds. In the evening when the weather is clear and the sun goes down, the ground heat begins to radiate into the air. In this way, in a certain range, the temperature rises with the height, and the sound rays bend downward. Most of the sound energy propagates along the ground, and the energy loss is very small, so people can easily hear the sound. China's folk summary that "the train is loud and the weather will be fine" coincides with this law. Grassroots meteorologists also regard thunder in summer evening as an auxiliary index of weather forecast.

At noon in summer and autumn, the underlying surface heats up, and the highest temperature of bare land can reach above 60℃, and the temperature of cement and asphalt pavement is higher. In contrast, the air temperature is lower (the temperature generally does not exceed 40℃). So at noon in summer, the surrounding environment is very quiet, which is a good time for lunch break. At night, the ground has cooled, the temperature has dropped slightly, the sound waves bend downward, and the surrounding sounds can be heard clearly, especially in rural areas where the underlying surface is mostly mud, and the sound transmission effect is more clear.