Only one answer to this.
OP is in the vicinity of Groom Lake, and Molecular displacement caused by the lake activity has caused the 2 different metals in the bimetallic coils to become a single cohesive substance.
As long as you don’t hear muffled helicopter noises at night, you should be safe but don’t let on that you know.
And that’s about the only thing i could think of that makes less sense than what the OP is having happen.
How the heck are bi metallic springs massively dying at the OP’s house?
Corrosion and severe over heating are about the only things i have ever seen kill the spring where they dont even work inaccurately anymore.
Appreciate everyone’s feedback. This has bugged me for years and my curiosity has grown with every dial thermometer thrown in the trash, but I couldn’t find anything online that would explain it. I even waited until all the teenagers moved out of the house and the next set died, so that eliminated one of my suspicions. I guess it’s just one of those mysteries.
I"ll bite the bullet and spend a little more money for a digital type next time – see if it survives. If it doesn’t, I’ll get one of those really bright lights and interrogate my husband and the dog until somebody confesses something that brings me peace on the matter.
Great tips, although the only one of these things that would have happened at our house is possibly the dropping – I don’t put my thermometers in the dishwasher or use them for anything except what they are labeled for. I haven’t asked Dear Hubby if he’s been dishwashing the meat thermometer, though, so you might have solved that mystery. Still, there’s the little oven thermometer … I can’t see him dishwashing that, I can’t even imagine him using it. I’ll go Columbo on him at dinner one of these first nights and see what I can learn. I assume there’s some perfectly rational explanation behind all this, I’d just like to know what it is so I can stop it from happening.
I have two consumer-grade dial thermometer/hygrometer/barometers that are 60 years old. Both survived a household move, and both appear to be accurate, at least within reason. They have never been outside the range of 500-1000 ft above sea level. I even beat one up pretty good doing “science” experiments as a kid, and it still works fine.
They would most likely be RTD technology or more rarely use a type J or type K thermocouple (WIKI). Not interchangeable in the circuitry but all three are just as efficient, accurate, and reliable for what you seem to want them for. In industry, I’ve used more thermocouples. RTDs are cheaper and easier to set up. The thermocouples are more likely in heating appliances like your oven, water heater, and furnace.