What factors affect the speed of sound?

The speed of sound is affected by the medium, temperature, pressure, and humidity.

The medium through which sound travels is one of the most significant factors. Sound moves faster in solids than in liquids, and faster in liquids than in gases. This is because particles in solids are more closely packed together, allowing vibrations to transfer more quickly from one particle to the next. For example, sound travels at about 343 metres per second in air, but it can travel at around 1,480 metres per second in water and up to 5,120 metres per second in steel.

Temperature also plays a crucial role in the speed of sound. In general, sound travels faster in warmer conditions. This is because higher temperatures provide more energy to the particles in the medium, causing them to vibrate more rapidly and transfer sound waves more efficiently. For instance, the speed of sound in air at 0°C is approximately 331 metres per second, but it increases to about 343 metres per second at 20°C.

Pressure has a less direct effect on the speed of sound in gases. While increasing pressure at a constant temperature does not significantly change the speed of sound, it can have an impact when combined with changes in temperature and density. In liquids and solids, pressure changes can alter the material's density and elasticity, thereby affecting the speed of sound.

Humidity, or the amount of water vapour in the air, also influences the speed of sound. Higher humidity levels mean there are more water molecules in the air, which are less massive than nitrogen and oxygen molecules. This reduces the overall density of the air, allowing sound to travel faster. For example, sound travels slightly faster on a humid day compared to a dry day.

Understanding these factors helps us analyse how sound behaves in different environments, which is essential for various applications, from designing concert halls to improving sonar technology.