Experts have conducted several researches to study the scientific phenomenon behind the whistling of teakettles. They explain it in terms of a steam kettle’s fluid dynamics. Why kettles whistle is actually a double mechanism process. The process initiates due to the steam produced in a kettle when the water is boiled. The steam produced in the kettle starts moving upwards. A kettle acts as a resonator in which the steam starts resonating and contracting. This contraction of steam makes it form a jet. It all depends on the speed of this steam jet how it would be funneled through the spout.
If an intense steam jet, exceeding a particular flow speed, is forced to flow through the spout, it starts making sound that is usually produced by small vortices. These vortices produce sound at certain frequencies. This is what we usually call the whistling of a kettle. This phenomenon was scientifically studied by researchers when they forced the air out at varied speeds. They observed and recorded the amplitudes and frequencies of these sounds. Their final analyses led to the real explanation of this phenomenon of a whistling kettle.
The conclusions derived by these researchers suggested that a whirling mass of air is produced when the steam reaches the spout of the kettle. Just before the whistle is going to start, the steam meets a hole that is much narrower than a kettle’s spout itself. That is how the steam flow is contracted while entering the whistle. A contraction of steam turns it into an unstable and disturbed jet. As the jet is not stable, it obviously cannot pass through the whistle in a perfectly smooth manner. During the exit, a pressure pulse is formed that further leads the steam to form musical vortices. That is the whole process of a kettle’s music reaching our ears.
