If a gas tap is turned on for a few seconds, someone a couple of meters away will hear the gas escaping long before he or she smells it. What does this indicate about the speed of sound and the motion of molecules in the sound-carrying medium?
The observation that someone hears the sound of escaping gas before they smell it can be explained by understanding the speed of sound and the motion of molecules in the sound-carrying medium.
In this case, the sound of the gas escaping reaches the person's ears faster than the smell of the gas reaches their nose. This indicates that sound travels much faster than the movement of gas molecules.
Sound is a mechanical wave that propagates through a medium, such as air. The speed of sound in a given medium depends on various factors like temperature, density, and elasticity of the medium. In general, the speed of sound in air at room temperature is around 343 meters per second (or approximately 1,235 kilometers per hour).
On the other hand, the motion of gas molecules is relatively slow compared to the speed of sound. When the gas tap is turned on, the molecules of the gas begin to move and spread, but their motion is relatively sluggish and takes some time to disperse and reach the person's nose.
Therefore, the speed of sound is significantly faster than the motion of gas molecules, resulting in the person hearing the sound of the escaping gas before they smell it.