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Re: [Phys-L] Singing Kettle

Congratulations to Jeffrey for identifying a fruitful line of investigation. As it happened, my wife returned from a European trip two hours later, and almost immediately asked, "What's wrong with the kettle?    The power light is turning on and off."

In self defense, I should say that I am left handed, so the dim indicator light faces the wall when I handle the kettle.
I examined the clockwork, after defeating the anti-tamper precautions: fixing screws with a three-lobe indentation for a kind of three legged philips screw-driver, which I rendered amenable to the efforts of a straight-edge screwdriver, using a dremel.
The design layout was sparsely elegant - except the two pole switch was carried on long copper fingers, one of which was noticeably discolored and heating one of the several overheat thermostats enough to push the contact out of contact with the cooked fixed contact support.    After ordering a replacement on line - as most things are obtained, lately - I did what I could to renew my handiman cred by fixing the old one.

Thanks for spotting the issue Jeffrey!

Brian W

On 10/24/2018 2:06 PM, Jeffrey Schnick wrote:
It would be easy to rule out a thermostat or heat-sensitive electrical fault by monitoring the current.

-----Original Message-----
From: Phys-l <> On Behalf Of brian whatcott
Sent: Wednesday, October 24, 2018 2:58 PM
To: prefered phys-l address <>
Subject: [Phys-L] Singing Kettle

We use an electric water kettle, made by Hamilton Beach; its capacity is
1.7 liters, electrified through its fixed base plate supplying 1.5kilowatts. The
shape is a truncated parabola of revolution, focus up.
When half filled, it shows a distinct acoustic pattern when the heating
produces gas bubbles. The sound oscillates on a 10 second periodic time,
from silence to a quiet pink noise and back, never louder than 60 dBm. I
suppose there is a positive feedback loop of some kind.    Care to hazard a

Brian W

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