In case you were wondering:
The high-pitched note emitted by hot kettles has puzzled scientists for more than a century, but thanks to two steamed-up researchers at Cambridge University, the exact physics of a whistling kettle have been worked out ….
…. Steam produced by the kettle first meets a hole in the kettle’s spout, which is significantly narrower than the spout itself. As steam is forced through the narrow opening, it creates a “naturally unstable” jet, according to a written statement released by the university, “like the jet of water from a garden hose that starts to break into droplets after it has travelled a certain distance.”
When the now-imperfect jet of steam reaches the second opening, it “cannot escape perfectly . . . and as [it hits] the second whistle wall, [it forms] a small pressure pulse. This pulse causes the steam to form vortices as it exits the whistle. These vortices produce sound waves, creating the comforting noise that heralds a forthcoming cup of tea.”
Whistling kettles have been a puzzlement since at least the late 19th Century, when John William Strutt, Third Baron Rayleigh, published The Theory of Sound. Despite Strutt’s theories about the kettle whistle, he concluded that “much remains obscure” about the sound.
I had actually just figured the physics were well understood, since you can get some pretty cool kettle whistles out there. That is to say, if one can tune a kettle to play a D minor with a suspended seventh, it would seem fair to simply presume scientists actually knew what they were doing.
Let that be a lesson.
In a way, that makes it like saying, “I think”, when one can look it up on a smartphone. Even Rand Paul knows how to use Wikipedia … er … um … right. Never mind.
Plagiarism is bad, m’kay?
Anyway, yeah. Kettle whistle. Oh, right: Never presume; always find out.
Grenoble, Ryan. “Why Do Kettles Whistle? Science Has An Answer”. The Huffington Post. October 27, 2013.
Kaczynski, Andrew. “Rand Paul Has Given Speeches Plagiarized From Wikipedia Before”. BuzzFeed. October 29, 2013.