My thermostat uses the expansion/contraction of a drop mercury to conduct electricity and trigger when to turn off and on.Prindagelf t1_iy9nocp wrote
it's not entirely accurate, the assembly housing the Mercury and contacts sit on a metal spring, of a material I can't remember, the spring flexes as the temperature changes causing the Mercury to slide from one end of the glass to the other connecting the contacts
ksquires1988 t1_iy9ogky wrote
IIRC that metal spring is actually 2 metals. I think it's called a bi-metallic strip.
WFPBvegan2 t1_iy9pmy3 wrote
This is correct.
voodoohotdog t1_iyaywpb wrote
These are the correct answers. Thank you great Sages.
WFPBvegan2 t1_iyb0mif wrote
At your service my friend.
LazerWolfe53 t1_iyckgom wrote
This guy is also correct
darrellbear t1_iybvsvj wrote
It's called a mercury switch, used to be pretty common.
Significant-Funny-14 t1_iybltvo wrote
That is correct. I believe one piece of metal expands more with heat than the other, causing a flex rather than just extending very slightly
Iain_MS OP t1_iy9oze8 wrote
Oh cool! I just assumed it would be expansion based like a thermometer. Thanks for insight!
JSONJSONJSON t1_iyauebs wrote
Yep, thermos are very small tubes, so very slight volume change is apparent.
SFXBTPD t1_iybd7fy wrote
Well its the way they taper down from a large bulb. The volume only changes by about 2% from 0 to 100C
JSONJSONJSON t1_iybfkhz wrote
Nice. Thermometer fact. 👍
JSONJSONJSON t1_iybftwk wrote
Oh! Is that because of decreased rate of change at higher temps? So the scale we read is consistent.
damaltor1 t1_iy9zufa wrote
exactly. setting the temperature higher tips the vial to one side, and actually rising temperature tips it back to the other side. it will find its equilibrium point when set temp and measured temp are equal.
lorddoa t1_iy9r071 wrote
Yep. Us po' rednecks used mercury in straws as the trigger to make our parachutes deploy in our homemade rockets. Like you said, it was about completing the circuit as opposed to thermal expansion
Just be sure to wait until the fucker is on the launchpad before hooking the wires up ;)
restingsurgeon t1_iy9q38y wrote
It is a bimetallic strip IIRC
UnReAl0 t1_iyb0kp2 wrote
The really cool part is in the center dial with the numbers. Thats the heat anticipator that helps increase or decrease temperature overshoot in the room. Technology and stuff
Beneficial_Tough3345 t1_iyaf6nh wrote
It’s a bi metal spring
GrecoAP t1_iycn5zp wrote
Okay, but how do I change the temperature?
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