Here is an item I saw on the wonderful Nostalgia Online site. They have a large collection of vintage kitchen utensils, most of which I do recall from my childhood, and many of which I run into as I rummage in flea markets in search of computing history items. However, this one I’ve never seen before, and the ingenious way it solves a real problem simply blew my mind.
This, folks, is a milk heater. The problem it solves is that whereas a watched pot doesn’t boil, the moment you turn your back on it it’s liable to boil over, which in the case of milk makes a real mess.
The solution is this: you put the milk in the outer pan, and a little water in the central cylinder. Since the water will boil a little before the milk (remember your chemistry!), it will activate the steam whistle at the top and alert you that the milk will boil in a moment.
I remember when raising a baby I also wanted to solve the boiling problem for baby formula, but as an electro-optics student my thoughts were along lines of detecting the steam above the liquid by its optical absorption (I never realized that over-complicated scheme). But the whistling pot seen here is way better, I think – and it did get used, evidently!
You can see this, and lots more retro items, here. If you can read Hebrew you can even read all about them! 🙂